Restart Your Mac Using the Apple Menu
The quickest (and easiest) way to restart your Mac is by using the power options from the Apple menu on the desktop. First, select the “Apple” icon at the top-left corner of the computer’s interface.
In the menu that appears, select the “Restart” button.
Your Mac will now restart. Give your computer a minute to come back up and most of your lag or small issues should (hopefully) be fixed.