From macOS Sierra 10.2.2, you can take screenshots of the Touch Bar using keyboard shortcuts (shortcut keys) or the app “Grab”.
Mac - Take Touch Bar Screenshot with Shortcut, App “Grab”
App “Touche”
Mac - Taking Screenshots - Keyboard Shortcuts Mac App “Grab” - Takes a screenshot of the entire screen after 10 seconds Mac - Screenshot App “Eidetic” with timer
See here for how to use and set up the Touch Bar/Touch ID.
How to use and set up Touch Bar/Touch ID