Understand Account Credits for Overpayment

When a guardian overpays on an invoice, record the actual amount paid. Any amount beyond the invoice balance is automatically added to the guardian account as a credit. You can see the credit amount in the Activity section in the invoice details after you record payments (see the figure below). The Credit Balance also displays on the invoice itself. You can then apply credits to the guardian's next invoice or payment. 

For more information about recording payments, see Record Invoice Payments. To apply payments to invoices and payments, see Apply Credits to New Invoices and Apply Credits When Recording Payments.