Once you've set up your account with your gateway and transactions are working - you can add credit cards by going to the Stored Credit Cards widget on the Customer Detail screen:
Click the "+" to add a new card. This will take you to the screen where you can provide card details:
Cards are not stored within our software, but with the gateway, who handles PCI compliance, etc.
Note: If you update a customer's billing information in the gateway directly, you'll need to do the same in the software, and vice versa.
For more information on setting up credit card integrations in the app, see our article here
For Authorize.net Users:
If you are trying to add a Saved Credit Card to a customer and receiving the following error:
The element 'createCustomerPaymentProfileRequest' in namespace 'AnetApi/xml/v1/schema/AnetApiSchema.xsd' has invalid child element 'paymentProfile' in namespace 'AnetApi/xml/v1/schema/AnetApiSchema.xsd'. List of possible elements expected: 'clientId, refId, customerProfileId' in namespace 'AnetApi/xml/v1/schema/AnetApiSchema.xsd'.
The solution is you'll want to log into your Customer Information Manager (CIM) at authorize.net and enter/edit that customer's credit card information there.
Once that's done, you can add it to the software by entering the information in the "Manual CIM Id" tab rather than trying to type in the credit card number itself.