Near-field communication

Near-field communication (NFC) is a set of for  between two electronic devices over a distance of 4 cm (1½ in) or less. NFC offers a low-speed connection with simple setup that can be used to ping more-capable wireless connections.

Usage
NFC devices can act as electronic s and s. They are used in systems and allow, replacing or supplementing systems such as credit cards and  smart cards. This is sometimes called NFC/CTLS or CTLS NFC, with contactless abbreviated CTLS. NFC can be used for sharing small files such as contacts, and bootstrapping fast connections to share larger media such as photos, videos, and other files.

NFC in Apple devices
NFC was first adopted by the iPhone 6 and 6 Plus for use with Apple Pay. The iPhone 7 and 7 Plus with iOS 11 added support for reading NFC tags. AirTags use NFC to be identified by iPhones and 3rd-party devices when in lost mode.