Exit full screen allows you to make the Zoom window smaller on your screen.
You may want to use this if you need to access other material on your desktop.
A minimized screen usually contains only options for audio, video, and exiting the minimized screen.
Enter full screen (Exit Minimized Video) enlarges the Zoom window.
This will make more of the Zoom screen visible to you - sometimes when you minimize the Zoom screen, only certain features are visible.