Here’s how:
This option works on every MacBook Air model, on all versions of the macOS.
Click theApple menuin the top left corner of the screen, then clickRestart.
ClickRestartor let the timer count down.

Do this if you prefer it or if the computer isn’t responding to mouse clicks.
In those situations, a restart will often solve most problems.
FAQ
First, back up any important data you don’t want to lose.

Once it boots into Recovery Mode, selectreinstall macOS.
Press theShift+Command+3keyboard shortcut until a thumbnail appears in the corner of your screen.
choose the thumbnail to edit the screenshot or wait until it saves on your desktop.
Toupdate your Macbook Air, selectSystem Preferences>Software Update>Update Now.