Use apps in full screen on Mac
Many apps on your Mac support full-screen mode—an app fills the entire screen—so you can take advantage of every inch of the screen and work without desktop distractions.
On your Mac, move the pointer to the green button in the top-left corner of the window, then choose Enter Full Screen from the menu that appears or click the button
.
In full screen, do any of the following:
Show or hide the menu bar: Move the pointer to or away from the top of the screen.
Show or hide the Dock: Move the pointer to or away from the Dock’s location.
Move between other apps in full screen: Swipe left or right on the trackpad. See Use trackpad and mouse gestures.
To stop using the app full screen, move the pointer to the green button again, then choose Exit Full Screen from the menu that appears or click the button
.
To work in a bigger window without going full screen, maximize (or zoom) the window. Move the pointer to the green button in the top-left corner of the window, press and hold the Option key, then choose Zoom from the menu that appears or click the button 
. The window expands, but the menu bar and the Dock remain visible. To return to the previous window size, press and hold the Option key, then click the green button again.
You can also double-click an app’s title bar to maximize the window. If the app minimizes into the Dock instead, change the title bar setting in Dock preferences.
If you’re using an app full screen, you can quickly choose another app to use in Split View. Press Control-Up Arrow (or swipe up with three or four fingers) to enter Mission Control, then drag a window from Mission Control onto the thumbnail of the full-screen app in the Spaces bar. You can also drag one app thumbnail onto another in the Spaces bar.