A fingerprint recognition feature available on some Mac computers. With Touch ID, you can unlock your Mac and some password-protected items, use Apple Pay to make purchases on the web, and purchase items from the iTunes Store, App Store, and iBooks Store.
Touch ID is located at the top-right corner of the keyboard, next to the Touch Bar or row of function keys, depending on the model of your Mac.
To use Touch ID, place your finger on it. To set up Touch ID, choose Apple menu > System Preferences, then click Touch ID.
For more information about Touch ID, see this Apple Support article.