In addition to being able to see two views of the same document at the same time, you can also display two different Microsoft Word documents side by side. If you need to compare two documents, then viewing them side by side can be a helpful thing to do.
To view two documents side by side, open two documents in Word and then click View > Window > View Side By Side.This option is only available when you have more than one document open.
Word will then resize both windows so that they fit side by side, occupying an equal amount of space. You can navigate between the two windows as you would under normal circumstances: by using alt-tab or or by simply clicking the title bar of the window to make it active.
View Side By Side: Synchronous Scrolling
When you display two documents side by side like this, the synchronous scrolling button becomes available.
This button acts like an on/off switch, so synchronous scrolling is either active or inactive. As soon as you display two documents side by side, synchronous scrolling is switched on by default and this means that both documents will scroll together, regardless of which window you are scrolling in.
When synchronous scrolling is turned off, you can scroll the document in each window independently.
If you have resized any of the windows, you can reset them to their original sizes, occupying half the screen size each, by clicking the Reset Window Position button.
Displaying Side By Side If You Have More Than Two Documents Open
If you happen to have more than two documents open in Word, clicking the View Side By Side button triggers the display of the Compare Side By Side window. You must use this window to choose which document you want to display next to the current one.