Actors and operations in the authorization workflow
The payment authorization workflow is a process by which the user confirms or enters the shipping information you provide or request in the payment sheet and authorizes the app to submit the payment request for approval by the issuing bank of the payment card specified in the payment request. The user may also change the payment card to use to fund the payment request, in which case you might need to update the payment request's summary items (by adding surcharges for specific cards, for example).
The payment authorization workflow starts when your app presents the payment sheet (a PKPaymentAuthorizationViewController object) and ends with the user authorizing the payment request. (The user may cancel the transaction by tapping the Cancel button on the payment sheet.)
This diagram depicts the actors and operations that are part of the payment authorization workflow:
The workflow comprises four steps, as follows:
The app presents the payment...
