When you tap and pay for something using your smartphone, you are using a technology called near-field communication, or NFC. NFC allows two devices to communicate with each other when they are close together, typically within four inches. NFC is used in a variety of ways. For example, you can use it to: Make payments with Apple Pay, Google Pay, or Samsung Pay Share photos, videos, or files by tapping two NFC-enabled devices together Pair Bluetooth devices by tapping them together Exchange business cards by tapping two NFC-enabled devices together When you tap and pay, your smartphone communicates with the merchant's NFC reader to complete the transaction. The NFC reader is usually attached to the point-of-sale terminal. To use tap and pay transactions , your smartphone must be NFC-enabled and have a supported tap and pay app installed. Supported tap and pay apps include Apple Pay, Google Pay, and Samsung Pay. You will also need to have a supported NFC-enabled credit or debit car...