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
On MacBook models with an Eject key, press and hold Control + Command + Eject
If the Mac still does not respond, disconnect all external devices and try again
If the battery is removable, remove it, then reinstall it and turn the Mac back on