When working on long documents it is sometimes useful to be able to see and edit other sections of the text at the same time. Word will let you do exactly that, though unless you stumble on the feature by accident you’ll probably never know it exists.
It’s really easy to use, all you have to do is:
point, click and drag the tiny separator bar that’s immediately above the arrow on the vertical scroll bar.
Drag it down to halfway and you have two separate views of the same document, each with their own scroll bars so you can move around both sections of the document independently.
To revert to the normal single pane view, slide the separator bar of the screen.