Open the Wallet app on your iPhone
Tap the plus sign
Select Debit or Credit Card
Follow the on-screen instructions
Enter your card details manually or scan your card
Verify your card with your bank if prompted
Set a default card if needed
Make sure Face ID, Touch ID, or a passcode is enabled
Use Apple Pay in stores by double-clicking the side button or Home button and authenticating
Use Apple Pay in apps or online by selecting Apple Pay at checkout