Card on File (CoF)

When card details are stored to streamline the checkout process for returning customers. This can be used for one-click payments, pay-per use services, or any recurring payment that does not follow a fixed schedule.

A recurring payment that occurs on a fixed schedule is referred to as a subscription.

If a merchant is PCI-Compliant at Level 1/Level 2, they can store card details by themselves. Otherwise, they must store card details using a payment service provider like Adyen.