Near Field Communication (NFC) is a set of standards for smartphones and similar devices to establish radio communication with each other by touching them together or bringing them into close proximity, usually no more than a few centimeters.
NFC can be used to share small amounts of data between two NFC-enabled devices, such as sharing a photo or video, exchanging contact information, or pairing Bluetooth devices. NFC can also be used to make payments by tapping the phone against a NFC-enabled payment terminal.
Most newer Android phones and iPhones have NFC built-in, and there are also many NFC-enabled accessories, such as NFC stickers and key fobs, that can be added to non-NFC phones.