Press and hold the power button until the Mac turns off
Wait 10 seconds
Press the power button again to turn it back on
If the Mac has Touch ID, press and hold Touch ID until it turns off
If the screen is frozen but the Mac still responds, press Command + Control + Power
If that does not work, press and hold Option + Command + Esc to force quit unresponsive apps
If needed, press and hold Control + Command + Power to restart immediately
On MacBook models with a removable battery, shut down, remove the battery, then reinstall it and turn it on
If the Mac still will not restart, unplug all accessories and try again