Look for the Apple Pay icon during checkout. When Apple Pay is selected as the payment method
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
When you are ready, make your purchase. Place your finger on Touch ID, completed Facial Recognition or enter the device passcode.
If using a Apple Watch double-click the side button to authorize payment.
After your payment information sends successfully, you’ll see 'Done' and a checkmark on the screen.