Apple Pay is a mobile payment and digital wallet service provided by Apple. It allows users to make contactless payments using their iPhone, Apple Watch, iPad, or Mac.

To use Apple Pay, users need to add their credit or debit card information to the Wallet app on their device. They can also add loyalty cards, gift cards, and other types of payment cards. Once the cards are added, users can make payments by holding their device near a contactless payment terminal and authenticating the payment with their fingerprint, Face ID, or passcode.

Apple Pay uses near-field communication (NFC) technology to transmit payment information securely between the device and the payment terminal. The payment information is encrypted and stored on the device's secure element, a dedicated chip that provides additional security for payments.

Apple Pay also works with online and in-app purchases. Users can select Apple Pay as their payment method and authenticate the payment using Touch ID, Face ID, or passcode.