hello, my sister has the MacBook air with the Touch ID and all of a sudden, it stopped turning on, we tried clicking the shift control and command keys with the power button but it still doesn't want to turn on. what should we do?

First connect the power supply then push on the power button and keep holding down until you see a screen appear with "options". Click on options and try to go to disk utilities and then disk repair. If that still does not work then contact Apple Support as ku4hx suggested..

As provided on the site you came from:

"If your Mac still doesn't turn on, please contact Apple support. "

This forum is not Apple support. Get Support