You can categorize it as a transfer in QuickBooks Online, Cyrus.
If the transaction appears in the bank feed, categorize it as a Record as Transfer, as it was only a mistake deposit to your business account. Here's how:
- In your Transactions, go to Bank Transactions and locate the deposited cheque.
- Click it and select Record as transfer.
- In the Transferred from, choose the account where it was from.
- After that, hit Add.

If you accidentally record a deposit to your business account in QuickBooks, you can correct it by transferring the funds to the appropriate account. During the process, you can contact your accountant for guidance.
Once done, I recommend reconciling your accounts in QBO to ensure all transactions match those in your bank or credit card account.
This thread will remain open for more questions or clarifications about managing cheques or other QBO concerns. We're always here to help.