docs: fix typo

apps/docs/src/guide/transactions/transaction-request.md

@@ -50,7 +50,7 @@ Predicates are used to define the conditions under which a transaction can be ex
 
 ### Adding a Witness and Signing a Transaction Request
 
-The SDK provides a way of either modifying the witnesses for a transaction request directly, or by passing accounts. This will then signing the transaction request with the account's private key. Below will detail how to add a witness to a transaction request:
+The SDK provides a way of either modifying the witnesses for a transaction request directly, or by passing accounts. This will then sign the transaction request with the account's private key. Below will detail how to add a witness to a transaction request:
 
 <<< @/../../docs-snippets/src/guide/transactions/transaction-request.test.ts#transaction-request-6{ts:line-numbers}