diff --git a/code/diacritics_fix.py b/code/diacritics_fix.py
index 7b28edd..5ab461a 100644
--- a/code/diacritics_fix.py
+++ b/code/diacritics_fix.py
@@ -6,12 +6,18 @@
 REMEDIED_CHARS = {ord(c): c for c in 'ĂăÂâÎîȘșTtȚțEeÉéÈèÊêËëIiÍíÌìÎîOoÓóÒòÔôÖöŐőUuÚúÙùÛûÜüŰűNnÑñÇçSsŚśŠšZzŽž'}
 
 
-def on_key_press(e: tkinter.Event):
+# https://stackoverflow.com/questions/75846986/certain-characters-like-%c8%9b-and-%c8%99-become-question-marks-as-i-type-them-in-a-tkin
+def on_key_press(e: tkinter.Event) -> str:
     """
-    ...
+    This function remedies a bug that made it impossible to type certain diacritics by finding those characters in the
+    input and replacing them properly.
+
+    Returns
+    -------
+    str
+        'break'.
     """
     char = REMEDIED_CHARS.get(e.keysym_num)
     if char:
         e.widget.insert('insert', e.char[:-1] + char)
         return 'break'
-
diff --git a/code/main.py b/code/main.py
index 19a0b0b..d61dd3c 100644
--- a/code/main.py
+++ b/code/main.py
@@ -72,7 +72,7 @@ def __init__(self, master: customtkinter.CTkTabview, **kwargs):
             i += 1
 
 
-def resize(root_window: tk.Tk, event: tk.Event = None):
+def resize(root_window: tk.Tk, event: tk.Event = None) -> None:
     """
     This function aims to reduce resizing lag.
 
@@ -82,6 +82,10 @@ def resize(root_window: tk.Tk, event: tk.Event = None):
         The main window of the app.
     event:
         Necessary for executing the function when the user resizes.
+
+    Returns
+    -------
+    None
     """
     root_window.update_idletasks()
 
@@ -108,12 +112,16 @@ def __init__(self):
         self.bind('<Configure>', lambda a: resize(self))
 
 
-def main():
+def main() -> None:
     """
     Called upon starting the program,
     this function uses the Tkinter module to create a window, notebook,
     two frames the user can switch between,
     and a basic configuration.
+
+    Returns
+    -------
+    None
     """
     root = App()
     root.mainloop()
diff --git a/code/password_generation/diceware_gui.py b/code/password_generation/diceware_gui.py
index 101d4bb..585cf84 100644
--- a/code/password_generation/diceware_gui.py
+++ b/code/password_generation/diceware_gui.py
@@ -91,6 +91,10 @@ def show_copy_menu(event: tk.Event) -> None:
             ----------
             event: tkinter.event
                 Gets the coordinates of the mouse cursor when the user releases a mouse button on a password_label.
+
+            Returns
+            -------
+            None
             """
             self.copy_menu.tk_popup(event.x_root, event.y_root - 30)
 
@@ -99,6 +103,10 @@ def show_copy_menu(event: tk.Event) -> None:
         def clear_window() -> None:
             """
             This function clears the window of any output widgets.
+
+            Returns
+            -------
+            None
             """
             self.widget_text_dict = {}
 
@@ -125,8 +133,11 @@ def insert_text(textbox: customtkinter.CTkTextbox, text: str) -> None:
             Called when the user 'rolls the dice' from the display_words function,
             this function aims to take a customtkinter Textbox,
             insert text into it, and bind it to show a copy pop-up menu when the user right-clicks.
-            """
 
+            Returns
+            -------
+            None
+            """
             textbox.configure(state='normal')
             textbox.delete('1.0', 'end')
             textbox.insert('1.0', text)
@@ -143,6 +154,10 @@ def display_words(pair: dict) -> None:
             ----------
             pair: dict
                 Contains the pairs of dice roll numbers and related words according to the dice ware wordlist.
+
+            Returns
+            -------
+            None
             """
             text_height = 1
             text_padx = 10
@@ -197,6 +212,10 @@ def show_passwords() -> None:
             """
             Called when the user clicks the show button,
             this function shows all passwords.
+
+            Returns
+            -------
+            None
             """
             if self.widget_text_dict != {}:
                 for widget, text in self.widget_text_dict.items():
@@ -210,6 +229,10 @@ def hide_passwords() -> None:
             """
             Called when the user clicks the hide button,
             this function hides all passwords.
+
+            Returns
+            -------
+            None
             """
             for widget, text in self.widget_text_dict.items():
                 widget.configure(state='normal')
@@ -234,6 +257,10 @@ def hide_passwords() -> None:
         def close_second_window() -> None:
             """
             This function destroys the window when it is closed.
+
+            Returns
+            -------
+            None
             """
             self.destroy()
             self.master.deiconify()
@@ -243,6 +270,10 @@ def close_second_window() -> None:
     def show_icon(self) -> None:
         """
         This function shows the icon of the toplevel window.
+
+        Returns
+        -------
+        None
         """
         self.deiconify()
         self.iconbitmap('textures/logo.ico')
diff --git a/code/password_generation/diceware_logic.py b/code/password_generation/diceware_logic.py
index 7596b85..2e0eade 100644
--- a/code/password_generation/diceware_logic.py
+++ b/code/password_generation/diceware_logic.py
@@ -13,6 +13,11 @@ def roll_dice() -> dict:
     Called when the user clicks the 'dice roll' of the diceware frame,
     this function returns a random pair of the number formed by 5 dice rolls
     and the associated word with that number, according to the diceware wordlist.
+
+    Returns
+    -------
+    dict
+        The final pair of 5 dice rolls and the corresponding diceware word.
     """
     final_pairs = {}
     dice_roll = ''
@@ -36,6 +41,10 @@ def copy_selected_text(labels: list) -> None:
     ----------
     labels: list
         The list of labels containing passwords.
+
+    Returns
+    -------
+    None
     """
     try:
         for label in labels:
@@ -54,6 +63,10 @@ def copy_selections(checkboxes_text_boxes: dict) -> None:
     ----------
     checkboxes_text_boxes: dict
         The dict chaining together each checkbox to each respective password textbox.
+
+    Returns
+    -------
+    None
     """
     text_to_be_copied = ''
     for key, value in checkboxes_text_boxes.items():
diff --git a/code/password_generation/generate_password_gui.py b/code/password_generation/generate_password_gui.py
index 079f5a8..ca91fdd 100644
--- a/code/password_generation/generate_password_gui.py
+++ b/code/password_generation/generate_password_gui.py
@@ -27,7 +27,6 @@ class PasswordGenerationFrame(customtkinter.CTkFrame):
     (length and character sets),
     and serves as a hub for all other password generation functions.
     """
-
     def __init__(self, master: customtkinter.CTkFrame, **kwargs) -> None:
         super().__init__(master, **kwargs)
         self.gui_font_name = 'Roboto'
@@ -69,6 +68,10 @@ def clear_text_label(textbox: customtkinter.CTkTextbox) -> None:
             ----------
             textbox: customtkinter.CTkTextbox
                 The text label to be cleared.
+
+            Returns
+            -------
+            None
             """
             textbox.configure(state='normal')
             textbox.delete('1.0', 'end')
@@ -86,6 +89,10 @@ def show_password(indicator: int, btn: customtkinter.CTkButton) -> None:
                 The number of the button that was clicked.
             btn: customtkinter.CTkButton
                 The button that was clicked.
+
+            Returns
+            -------
+            None
             """
             # https://stackoverflow.com/questions/68327/change-command-method-for-tkinter-button-in-python
             btn.configure(text='HIDE', command=lambda: hide_password(indicator, btn))
@@ -116,6 +123,10 @@ def hide_password(indicator: int, btn: customtkinter.CTkButton) -> None:
                 The number of the button that was clicked.
             btn: CTKButton
                 The button that was clicked.
+
+            Returns
+            -------
+            None
             """
             btn.configure(text='SHOW', command=lambda: show_password(indicator, btn))
 
@@ -141,6 +152,10 @@ def run_function_based_on_slider_value(value: float) -> None:
             ----------
             value: float
                 The slider's value
+
+            Returns
+            -------
+            None
             """
             if value == 0:
                 hide_all_passwords()
@@ -153,6 +168,10 @@ def show_all_passwords() -> None:
             this function goes through each password_label,
             inserts the specific password inside of it through the show_text function,
             and changes the button into a hide all button.
+
+            Returns
+            -------
+            None
             """
             for indicator, btn in enumerate(self.show_hide_buttons):
                 show_password(indicator, btn)
@@ -162,6 +181,10 @@ def hide_all_passwords() -> None:
             Called when the user clicks the 'hide all' button,
             this function goes through each password_label,
             and clears it.
+
+            Returns
+            -------
+            None
             """
             for indicator, btn in enumerate(self.show_hide_buttons):
                 hide_password(indicator, btn)
@@ -369,6 +392,10 @@ def show_copy_menu(event: tkinter.Event) -> None:
             ----------
             event: tkinter.Event
                 Gets the coordinates of the mouse cursor when the user releases a mouse button on a password_label.
+
+            Returns
+            -------
+            None
             """
             # https://stackoverflow.com/questions/69425865/tkinter-event-x-y-mouse-position-wrong-value-only-when-mouse-movement-up
             self.copy_menu.tk_popup(event.x_root, event.y_root - 30)  # https://youtu.be/Z4zePg2M5H8
@@ -399,6 +426,10 @@ def create_password_labels(event) -> None:
             ----------
             event: tk.Event
                 Necessary for running the function when the user presses the RETURN key.
+
+            Returns
+            -------
+            None
             """
             message = logic.determine_error(
                 logic.validate_character_sets(self.lowercase_letters_var, self.uppercase_letters_var,
@@ -503,6 +534,10 @@ def show_text(textbox: customtkinter.CTkTextbox, message: str) -> None:
                 or the first password label if an error is generated.
             message: str
                 Each password or the error.
+
+            Returns
+            -------
+            None
             """
             textbox.configure(state='normal')
             textbox.delete('1.0', 'end')
@@ -514,6 +549,10 @@ def open_other_methods(self) -> None:
         """
         Called when the user clicks on the 'try other methods' button,
         this function creates a Toplevel window containing other methods of password generation.
+
+        Returns
+        -------
+        None
         """
         if self.other_methods_window is None or not self.other_methods_window.winfo_exists():
             self.other_methods_window = other.OtherMethodsWindow(self)
diff --git a/code/password_generation/generate_password_logic.py b/code/password_generation/generate_password_logic.py
index a420a70..3c773a9 100644
--- a/code/password_generation/generate_password_logic.py
+++ b/code/password_generation/generate_password_logic.py
@@ -67,6 +67,11 @@ def determine_error(valid_character_set_bool: bool, requested_password_length: s
         'An error occurred. Try again with at least 1 character set and a whole number between 4 and 100.'
     invalid_input_error: str
         'An error occurred. Try again with a whole number between 4 and 100.'
+
+    Returns
+    -------
+    str
+        The error to be shown to the user.
     """
     if valid_character_set_bool:
         try:
@@ -100,6 +105,11 @@ def validate_character_sets(lowercase_letters_var: tkinter.IntVar, uppercase_let
         The variable of the digits checkbox.
     punctuation_var: tkinter.IntVar
         The variable of the punctuation checkbox.
+
+    Returns
+    -------
+    bool
+        Whether or not there's at least 1 valid character set.
     """
     # https://www.reddit.com/user/Diapolo10/
     return any(var.get() for var in (lowercase_letters_var, uppercase_letters_var, digits_var, punctuation_var))
@@ -124,6 +134,11 @@ def generate_password(requested_password_length: int, lowercase_letters_var: tki
         The variable used to check if the digits checkbox has been selected or not.
     punctuation_var: tkinter.IntVar()
         The variable used to check if the punctuation checkbox has been selected or not.
+
+    Returns
+    -------
+    str
+        The password.
     """
     # Define all character sets that will be used in the password
     character_sets = []
@@ -155,12 +170,15 @@ def copy_selected_text(input_box: customtkinter.CTkEntry, labels: list) -> None:
         The entry box.
     labels: list
         The list of password labels.
+
+    Returns
+    -------
+    None
     """
     try:
         for label in labels:
             selected_text = str(label.selection_get())
             clipboard.copy(selected_text)
-
         input_box.focus_set()
     except (ValueError, TclError):
         # There is no need to warn the user when they try to copy nothing as it does not have any effect on the app
@@ -178,5 +196,9 @@ def copy_password(index: int, passwords: list) -> None:
         Which password_label has been selected to copy its password.
     passwords: list
         The list of generated password.
+
+    Returns
+    -------
+    None
     """
     clipboard.copy(passwords[index])
diff --git a/code/password_generation/other_methods_gui.py b/code/password_generation/other_methods_gui.py
index d619614..4eb447f 100644
--- a/code/password_generation/other_methods_gui.py
+++ b/code/password_generation/other_methods_gui.py
@@ -19,6 +19,10 @@ def open_link(url: str) -> None:
     ----------
     url: str
         The URL to be opened.
+
+    Returns
+    -------
+    None
     """
     webbrowser.open_new(url)
 
@@ -34,7 +38,6 @@ class CreateToolTip:
 
     Modified to include a delay time by Victor Zaccardo, 25mar16
     """
-
     # https://stackoverflow.com/questions/3221956/how-do-i-display-tooltips-in-tkinter
     def __init__(self, widget: customtkinter.CTkLabel, text: str = 'widget info') -> None:
         self.button_hover_color = None
@@ -51,6 +54,10 @@ def enter(self, event: tkinter.Event = None) -> None:
         """
         Called when the user hovers over the given widget,
         this function shows the tooltip.
+
+        Returns
+        -------
+        None
         """
         self.schedule()
 
@@ -58,6 +65,10 @@ def leave(self, event: tkinter.Event = None) -> None:
         """
         Called when the user moves out of the given widget,
         this function shows the tooltip.
+
+        Returns
+        -------
+        None
         """
         self.unschedule()
         self.hidetip()
@@ -66,6 +77,10 @@ def schedule(self) -> None:
         """
         This function cancels any previously shown tooltips,
         and defines a unique ID for a new tooltip.
+
+        Returns
+        -------
+        None
         """
         self.unschedule()
         self.id = self.widget.after(self.waittime, self.showtip)
@@ -73,6 +88,10 @@ def schedule(self) -> None:
     def unschedule(self) -> None:
         """
         This function cancels any previously shown tooltips.
+
+        Returns
+        -------
+        None
         """
         identification = self.id
         self.id = None
@@ -84,6 +103,10 @@ def showtip(self, event: tkinter.Event = None) -> None:
         This function creates a toplevel at the user's cursor's coordinates,
         creates a label within it,
         and removes any other window decorations.
+
+        Returns
+        -------
+        None
         """
         button_border_width = 2
         button_fg_color = 'blue'
@@ -114,6 +137,10 @@ def showtip(self, event: tkinter.Event = None) -> None:
     def hidetip(self) -> None:
         """
         This function destroys the toplevel.
+
+        Returns
+        -------
+        None
         """
         tw = self.tw
         self.tw = None
@@ -185,6 +212,10 @@ def __init__(self, *args, **kwargs):
     def show_icon(self) -> None:
         """
         This function shows the icon of the toplevel window.
+
+        Returns
+        -------
+        None
         """
         self.deiconify()
         self.iconbitmap('textures/logo.ico')
@@ -193,6 +224,10 @@ def open_diceware(self) -> None:
         """
         Called when the user clicks on the 'From the diceware' button,
         this function opens the diceware Toplevel window.
+
+        Returns
+        -------
+        None
         """
         self.withdraw()
         if self.diceware_window is None or not self.diceware_window.winfo_exists():
@@ -204,6 +239,10 @@ def open_sentence_input(self) -> None:
         """
         Called when the user clicks on the 'From a sentence' button,
         this function opens the sentence input Toplevel window.
+
+        Returns
+        -------
+        None
         """
         self.withdraw()
         if self.sentence_input_window is None or not self.sentence_input_window.winfo_exists():
diff --git a/code/password_generation/sentence_input_gui.py b/code/password_generation/sentence_input_gui.py
index 5159f07..7afcfd5 100644
--- a/code/password_generation/sentence_input_gui.py
+++ b/code/password_generation/sentence_input_gui.py
@@ -16,13 +16,7 @@ class SentenceInputToplevel(customtkinter.CTkToplevel):
     """
     def __init__(self, master: customtkinter.CTkToplevel, **kwargs) -> None:
         super().__init__(master, **kwargs)
-        """
-        Called upon starting the app,
-        this function prepares the 'input sentence' frame for when
-        the user wants to try other methods of password generation
-        by creating a basic Tkinter configuration, with an instruction, input,
-        and a way to display the produced password.
-        """
+
         self.geometry('900x300')
         self.title('Sentence input')
         self.iconbitmap('textures/logo.ico')
@@ -56,6 +50,10 @@ def show_copy_menu(event: tk.Event) -> None:
             ----------
             event: tk.Event
                 Gets the coordinates of the mouse cursor when the user releases a mouse button on a password_label.
+
+            Returns
+            -------
+            None
             """
             self.copy_menu.tk_popup(event.x_root, event.y_root - 30)
 
@@ -83,7 +81,7 @@ def show_copy_menu(event: tk.Event) -> None:
         self.copy_menu.add_command(label='Copy',
                                    command=lambda: logic.copy_selected_text(self.text_labels))
 
-        def highlight_sentence(event: tk.Event):
+        def highlight_sentence(event: tk.Event) -> None:
             """
             Called as the user types,
             this function calls the produce_password function of sentence_input_logic.py
@@ -94,6 +92,10 @@ def highlight_sentence(event: tk.Event):
             ----------
             event: tk.Event
                 Necessary for running the function as the user types.
+
+            Returns
+            -------
+            None
             """
             char_dict = {}
 
@@ -126,6 +128,10 @@ def show_password(password: str) -> None:
             ----------
             password: str
                 The password to be shown generated from the sentence.
+
+            Returns
+            -------
+            None
             """
             self.password_label.configure(state='normal')
             self.password_label.delete('1.0', 'end')
@@ -141,6 +147,10 @@ def display_warnings(warnings: list) -> None:
             ----------
             warnings: list
                 List of the tips for the user's password.
+
+            Returns
+            -------
+            None
             """
             self.warning_label_1.configure(text=warnings[0])
             self.warning_label_1.place(relx=0.5, rely=0.75, anchor='center')
@@ -158,6 +168,10 @@ def display_warnings(warnings: list) -> None:
         def close_second_window() -> None:
             """
             This function destroys the window when it is closed.
+
+            Returns
+            -------
+            None
             """
             self.destroy()
             self.master.deiconify()
@@ -167,6 +181,10 @@ def close_second_window() -> None:
     def show_icon(self) -> None:
         """
         This function shows the icon of the toplevel window.
+
+        Returns
+        -------
+        None
         """
         self.deiconify()
         self.iconbitmap('textures/logo.ico')
diff --git a/code/password_generation/sentence_input_logic.py b/code/password_generation/sentence_input_logic.py
index d067291..2e8dc33 100644
--- a/code/password_generation/sentence_input_logic.py
+++ b/code/password_generation/sentence_input_logic.py
@@ -8,7 +8,7 @@
 from tkinter import TclError
 
 
-def check_password_strength(inputted_password: str) -> list | str:
+def check_password_strength(inputted_password: str) -> list:
     """
     Called upon pressing the done button,
     this function defines several functions that check
@@ -16,12 +16,16 @@ def check_password_strength(inputted_password: str) -> list | str:
     and returns appropriate messages.
     It then calls these functions and returns a list of messages indicating the results of each check.
 
-    Returns an empty list when the inputted_password in None.
-
     Parameters
     ----------
     inputted_password: str
-        The input of the user
+        The input of the user.
+
+    Returns
+    -------
+    list:
+        List that contains tips for the user to improve their password.
+        An empty list when the inputted_password is None.
     """
     user_input = []
     user_input[:0] = inputted_password  # Adds each character of the input to a list.
@@ -138,6 +142,11 @@ def produce_password(char_dict: dict) -> list:
     ----------
     char_dict: dict
         The dictionary chaining each character to its index.
+
+    Returns
+    -------
+    list
+        The list of letters to be coloured and the produced password.
     """
     letters_to_be_coloured = {}
     password = ''
@@ -167,6 +176,10 @@ def copy_selected_text(labels: list) -> None:
     ----------
     labels: list
         The list of labels that contain text that could be copied.
+
+    Returns
+    -------
+    None
     """
     try:
         for label in labels:
diff --git a/code/password_strength/password_strength_gui.py b/code/password_strength/password_strength_gui.py
index 6a42d67..cde713f 100644
--- a/code/password_strength/password_strength_gui.py
+++ b/code/password_strength/password_strength_gui.py
@@ -24,7 +24,6 @@ class PasswordStrengthFrame(customtkinter.CTkFrame):
     an entry box for password input, and four warning labels to display the strength of the password.
     It also creates a menu for pasting text, which is triggered by a right-click on the input box.
     """
-
     def __init__(self, master: customtkinter.CTkFrame, **kwargs) -> None:
         super().__init__(master, **kwargs)
         title_font = customtkinter.CTkFont(family='Roboto', size=36)
@@ -79,6 +78,10 @@ def display_paste_button(event: tkinter.Event, paste_menu: tkinter.Menu) -> None
         Gets the coordinates of the mouse cursor when the user releases a mouse button on a password_label.
     paste_menu: tkinter.Menu
         The contextual menu containing the paste button.
+
+    Returns
+    -------
+    None
     """
     paste_menu.tk_popup(event.x_root, event.y_root - copy_button_y_offset)
 
@@ -97,8 +100,12 @@ def display_warnings(entry_box: customtkinter.CTkEntry, w_labels: list, event: t
         The input box of the password.
     w_labels: list
         Warning labels.
-    event: tkinter.event
+    event: tkinter.Event
         Necessary for initiating the function as the user types.
+
+    Returns
+    -------
+    None
     """
     for label in w_labels:
         label.configure(text='')
@@ -119,6 +126,10 @@ def paste_text() -> None:
     """
     Called upon pressing the paste button,
     this function uses the keyboard module to simulate pressing CTRL and V to paste text into the input_box.
+
+    Returns
+    -------
+    None
     """
     # https://youtu.be/DTnz8wA6wpw
     keyboard.press(Key.ctrl_l)
diff --git a/code/password_strength/password_strength_logic.py b/code/password_strength/password_strength_logic.py
index d379374..8a67ac2 100644
--- a/code/password_strength/password_strength_logic.py
+++ b/code/password_strength/password_strength_logic.py
@@ -28,6 +28,13 @@ def check_password_strength(inputted_password: str, input_password_msg: str) ->
         The input of the user
     input_password_msg: str
         'Please input a password.'
+
+    Returns
+    -------
+    list
+        If a password was inputted, this function will return the list of warnings/tips.
+    str
+        If no password was inputted, this function will return a message asking the user to input one.
     """
     user_input = []
     user_input[:0] = inputted_password  # Adds each character of the input to a list.