There are several ways to add credit to a Customer's account.
Payments Page
To add a credit to a customer's account from the payments page, click the "Finances" tab and "Payments."
Click the "Add payment" button.
Select the customer and select "Add as a customer credit" in the "apply to" section.
Select the date, enter the amount for the credit, and select the payment method.
If the customer has a card on file, you will see this message and will be able to select the card after clicking "Add Payment."
You will see this message if the customer does not have a card on file. You can add this credit, but a card will not be charged.
Customer Page
You can also add a customer credit by going to the "Customers" tab and click to edit the desired customer.
Then click the "Add Payment" button on the top of the screen.
This will take you to the page to edit and the option to Add as a customer credit.