Press and hold the Power button until the Mac turns off
Wait a few seconds
Press the Power button again to turn it back on
If your Mac has Touch ID, press and hold Touch ID until it shuts down
If the screen is frozen, press and hold Control + Command + Power button until the Mac restarts
On MacBooks with Touch Bar, press and hold Control + Command + Touch ID until the Mac restarts
If the keyboard shortcut does not work, press and hold the Power button for about 10 seconds, then press it again
If the Mac still does not respond, disconnect all external devices and try again