Hello there!
Thank you for reaching out to the Community. I’m here to help you issue a credit for the incorrect invoice.
Since the invoice has not been paid yet, you’ll want to void the incorrect invoice to avoid duplicates. Here’s how to do that:
- Go to Sales, then select All Sales.
- Find the invoice you want to void or delete.
- In the Action column, click the drop-down ▼, and select Void or Delete.

For more detailed information on voiding invoices, check out this article: Void or delete transactions in QuickBooks Online.
After voiding the incorrect invoice, you can issue a credit. Here’s how to create a Credit Memo:
- Click + New at the top left and select Credit Memo.
- Choose the customer's name from the Customer drop-down.
- Enter the item and the overpayment amount.
- Once you're done, click Save and close.
If you'd like to add the credit as a line item to a new invoice, you can create and apply a delayed credit instead.
Here are some helpful articles to guide you in recording payments and customizing your sales forms:
I'm always here to assist with any further questions about handling customer credits or anything else related to QuickBooks. Have a great day!