Complete the requirements needed to use Apple Pay in your apps.
To set up your environment to implement Apple Pay in your apps, you must complete three steps:
Create a merchant ID.
Create a Payment Processing certificate.
Enable Apple Pay in Xcode.
Follow the instructions in Configure Apple Pay (iOS, watchOS), which guide you to create the following:
Merchant ID. An identifier you register with Apple that uniquely identifies your business as a merchant able to accept payments. This ID never expires, and can be used in multiple websites and iOS apps. See Create a merchant identifier for the setup steps.
Payment Processing Certificate. A certificate associated with your merchant ID, used to secure transaction data. Apple Pay servers use the certificate’s public key to encrypt payment data. You (or your payment service provider) use the private key to decrypt the data to process payments. See Create a payment processing certificate for the setup steps.
Finally, you need to enable the Apple Pay capability in your Xcode project. See Enable Apple Pay for the setup steps.
For a video showing the configuration steps, see: Configuring Your Developer Account for Apple Pay.