How do I make Apple Pay payments within an app or on participating websites?
To pay in selected apps and on the web in Safari on your iPhone, iPad, Apple Watch, select Apple Pay at the check-out and complete the payment.
With Face ID glance at your screen, for Touch ID place your finger on Touch ID or you can enter the device passcode. For Apple Watch double-click on the side button.
Be sure to check your billing, shipping and contact information to make sure that they’re correct. If you want to pay with a different card, tap > next to your card.
If you need to, enter your billing, shipping and contact information. Apple pay will store that information, so you won’t need to enter it again.