Face ID

Face ID refers to Apple's facial recognition technology in devices equipped with TrueDepth front-facing cameras and DOT projector.

History
Face ID was first introduced in the iPhone X in November 2017. It is also supported in the 3rd generation iPad Pro and later, as well as recent iPhone models without a home button.

In early 2022, Apple began beta testing iOS 15.4, which allows for Face ID while wearing a mask by focusing on recognition of facial features around the eyes. However, this option is somewhat less secure than full facial recognition. When it was released on March 14, 2022, support for facial recognition with a mask was limited to the iPhone 12 series and higher.

Trivia
The TrueDepth sensor on the iPhone X and above is also used to animate Memoji.