How do I pay with Apple tap?

Pay with your iPhone

To use your default card: If your iPhone has Face ID, double-click the side button. ...
To use a different card, tap your default card to see your other cards. Tap a new card and authenticate.
Hold the top of your iPhone near the contactless reader until Done and a checkmark appear on the display.

Why is my Apple Pay not working?

Check that you're able to use Apple Pay: Contact your card issuer to see if they support Apple Pay. Update to the latest version of iOS, watchOS, or macOS. Confirm that you have Face ID, Touch ID, or a passcode set on your device.