The Rest API works by sending http calls to specific resources identified by URLs. The HTTP verb (e.g. GET or POST) defines the action on the resource.

Overview of the API entry points

OrdersCreate, list and query order details.
Order ItemsCreate and list order items.
PaymentsStart the Payment for a given Order.
CapturesCreate and update captures.
ShoppersCreate shopper details.
RefundsRefund an already processed payment.
SubscriptionsCreate and list subscriptions, and start recurring payments
Apple PayInitialize and authorize Apple Pay payments.
Google PayAuthorize Google Pay payments.
Additional payment dataManage additional payment method specific payment data.
TokenizationManage payment details tokenization.

For credit card payments authentication of the shopper is required. Details about credit card authentication can be found on Card Authentication .

Data Retention

Be aware that the offered services (APIs) cannot be used as an archive, as to protect end-consumer data the data will be removed.
If you need to keep the data for a prolonged period (for example due to taxation laws), then you must do that on your own accord according to the applicable laws.