First, it’s possible for you to use the Microsoft Word app.
Here is how to do that:
1.
Open your Microsoft Word.

Go toFile>Options>Advanced.
Scroll down to find theSavepart and uncheck theAlways create backup copyoption.
Go to the following path:
HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Word\Options
3.

Then, find theBackupDuringSavevalue and double-click it to change its value from1to0.
So, there are better ways to protect important Word files.
To do this task, there is a piece offree backup softwarefor you MiniTool ShadowMaker.

Download, install, and launch MiniTool ShadowMaker.
MiniTool ShadowMaker TrialClick to Download100%Clean & Safe
2.
After entering its main interface, go to theBackuppage.
ClickSOURCEand chooseFolders and Filesto select your Word files.
Then clickDESTINATIONto choose a target disk to save the backup image.
Its recommended to choose the external hard drive as the destination.
To set the incremental backup, you’re gonna wanna go toOptionsand clickBackup Scheme.
By default, theBackup Schemebutton is disabled and you oughta turn it on.