Apple Pay is a contactless mobile payment and digital wallet system for use in stores, within apps, or on websites when using the Safari browser. It converts a credit or debit card’s chip and PIN into a digital format and stores the information in an iPhone, iPad, Apple Watch, MacBook Pro or Mac desktop computer.
This allows the Apple device to communicate with contactless point of sale equipment in order to authorise a purchase, adding an extra level of security with either Touch ID (the user touching the device’s screen to enter a previously authenticated fingerprint) or a passcode.
Once your enabled credit card has been added to Apple Pay, you don’t need carry your credit card with you. You can just pay with your mobile device.