To record a customer overpayment in QuickBooks, issue a credit memo and receive the overpayment.

To issue a credit memo:

1. Go to + New > Credit memo.
2. Select the customer from the Customer dropdown menu.
3. Enter the date of the credit memo.
4. In the Items section, enter the invoice number and amount of the overpayment.
5. Click Save and close.

To receive the overpayment:

1. Go to + New > Receive payment.
2. Select the customer from the Customer dropdown menu.
3. Enter the date of the payment.
4. In the Payment details section, select Credit from the Payment method dropdown menu.
5. Enter the amount of the overpayment.
6. Click Save and close.

Note: You do not need to create a sales receipt for the overpayment.