The menu bar has been a fixture on the Mac since it launched in 1984, but since OS X El Capitan, you can hide the menu bar. Open System Preferences, go to General, then click "Automatically hide and show the menu bar."
When you tick this box off, the menu bar will reappear as you glide your mouse arrow towards the top of the screen, allowing you to get at all your menus.
When you tick this box off, the menu bar will reappear as you glide your mouse arrow towards the top of the screen, allowing you to get at all your menus.