A feature at the top of the keyboard on some Mac computers. You can use familiar gestures — like tap, swipe or slide — directly on the Touch Bar to adjust settings and perform tasks.
By default, the Touch Bar shows the Control Strip, which you can use to adjust settings like brightness and volume and ask Siri . You can expand the Control Strip to access additional settings.
Other buttons on the Touch Bar vary by app or task. For example, when you write an email in the Mail app, the Touch Bar shows buttons for formatting text.
See the Apple Support article How to use the Touch Bar on your MacBook Pro.