Yes. You can manually apply credit to a customer's account by navigating to the Payments & Credits tab on the customer card. In the "manually add credit" field, use the the "+" prefix, plus the credit amount, and click save. The credit will be added to the customer account.
To credit a customer for a returned product or cancelled order, please refer to the Returns, Credits and Refunds section.
Last Modified: 18/11/2016