Ok, so this isn’t really an Office feature, but it is quite a nifty Windows feature. Mac has a similar option.
Have you ever wanted to keep one window static while working in another window? For example, writing in Word while researching in Chrome. It’s a bother to go back and forth between windows or to resize the windows, right? How about a third window? A fourth?! This is madness, Joshua!
Just choose a window, and drag it all the way to the left or to the right of the screen. You’ll notice a flash. Release the mouse, and that window will now remain static on exactly half the screen. Other open windows will appear on the opposite side of the screen so that you can select the second window to occupy the second half of the screen. Nifty. (Be sure that you’ve enabled multi-tasking in settings.)
On Mac, at the top left of a window, long click the green dot that takes a window into full screen. The long click splits the screen and places that window on one side, allowing you to choose the second window.
These folks explain it quite well.
This is especially helpful during Zoom meetings. Enjoy!