Welcome to the Community. Let me show you how to handle the credit note in QuickBooks.
To apply it, you can open the invoice and press the Receive payment option. From there, you'll be able to view the unapplied credits, which you can apply to the transaction.
Here's how:
On the left navigation bar, click Sales.
Go to the Customers tab.
Click the customer name.
Search for the invoice, then press the Receive payment option.
Under Outstanding Transactions, put a checkmark on the box beside the invoice.
Below Credits, put a checkmark on the box beside the credit note.