Tap to pay is the common term for paying by bringing a contactless card or a device with a mobile wallet within a few centimeters of a payment terminal. The card or device and the reader exchange data by near-field communication, and the chip produces a one-time code that the issuer checks when it authorizes the transaction. Nothing is inserted or swiped, and for small amounts no PIN or signature is needed.
The technical name is contactless payments. Card payments above the contactless transaction limit set in each country require a PIN, while phone and watch payments are verified on the device by fingerprint, face or passcode and are generally not subject to that limit. Tap to pay is also used as a product name for SoftPOS, where a merchant accepts contactless payments directly on a smartphone, as in Tap to Pay on iPhone and Tap to Pay on Android.