With new full-screen support, Outlook 2016 for Mac helps you manage multiple email messages more easily. The current message—the one you're reading or composing—gets full focus, while others await your attention in the tray at the bottom of your screen. And your inbox remains visible at all times so you can switch back and forth as often as you need to.
Switch to Full Screen view
Switching to Full Screen view is easy as pushing a button. The button is at the top left of your Outlook screen:
Click the button again to leave Full Screen view. Any open messages will be tiled.
Tip: You can also enter and leave full-screen view by clicking Ctrl + + F