Assign Primary Monitor on Apple With Multiple Displays

You’d think it was easy to assign which monitor was the primary display on a Mac, but it’s elusive. Oddly enough, the Apple Help system is garbage and doesn’t quickly show you what to do. It’s as simple as a drag-drop action in System Preferences > Displays. Your Mac displays will reset, then the menubar above and dock below should be on the new primary display. The screen shot below should help make sense of this procedure.

Primary Display Assignment System Preferences