How to use Apple Pay on your Apple Watch | Apple Support

To set up Apple Pay on your Apple Watch, first ensure your iPhone and Apple Watch are close together. Open the Apple Watch app on your iPhone, scroll down, and tap “Wallet & Apple Pay.” If you already use Apple Cash on your iPhone, it’s automatically enabled on your watch. To add a new card, tap “Add Card” or select a card you use on your iPhone. Follow the on-screen instructions to complete the process. Once added, the card will be your default payment option. To make a purchase, double-click the side button on your watch, select your card, and hold the watch near the contactless reader.

Summary:
– Ensure your iPhone and Apple Watch are close together.
– Open the Apple Watch app on your iPhone and go to “Wallet & Apple Pay.”
Add a new card or select an existing card from your iPhone.
– Follow on-screen instructions to complete the card setup.
– To pay, double-click the side button on your watch, choose the card if needed, and hold the watch near the contactless reader.