How do you close all open apps on a Mac?

The Keyboard Shortcuts to Quit All Apps
  1. Quit all apps at the same time. CMD + Option (Alt) + ESC. CMD + A. Enter.
  2. Quit all apps one-by-one. CMD + Tab. CMD + Q.

How do I close all windows at once?

A little-known set of keystrokes will shut down all active programs at once in no time. Press Ctrl-Alt-Delete and then Alt-T to open Task Manager’s Applications tab. Press the down arrow, and then Shift-down arrow to select all the programs listed in the window.