Once an invoice has been credited, it reduces the owed balance of that customer as the customer now has two invoices – one for a positive amount and the other for the same amount as a negative.

This doesn’t however use the credit, which needs to be applied to an invoice. Customers don’t have to apply the credit to the corresponding invoice, but can save it for later when they want to apply the credit to a different invoice.

To apply the credit to an invoice

Open the Customers module and go the Payments module. Just like a payment, choose Add to create a new payment.  Select the customer who has the credit to be applied.

Locate the Credit and the invoice to apply the credit to. The credit can be identified as it will have a negative remaining balance:

To apply the credit in full, use the Pay in Full arrows on the credit line first. This will then allow that amount to be applied to an unpaid invoice using the Pay in Full arrows.

Once applied, use Post to complete applying the credit to an invoice.