To define and activate payment methods your company supports, click your username at the top right and navigate to Settings > Payment Method. The payment methods you select will appear in a picklist when you set up the billing and payment terms for a customer within the customer account. 

Note that you can create payment methods using the API operations even if the payment method type is not selected on the Customize Payment Methods page.

Each time the Customize Payment Methods page is loaded, any changes to the system payment method types made since the last page load are recorded as Payment Method Type setting changes in the Audit Trail. For example, if Apple Pay was introduced as a new supported payment method type since the last page load, a record for its addition is created in the Audit Trail, even if Apple Pay is not enabled on your tenant.

See Define Payment Methods for more information about the supported payment methods.