Ever wish you could restore a previous version of a Word document or an Excel spreadsheet? Well if you are an Office 365 subscriber using SharePoint, OneDrive, and OneDrive for Business, you can! Office 2016 automatically saves versions of your files while you’re working on them. This feature allows you to see how files have changed between versions or even restore to an older version should the need arise.
In Word, you can view and restore previous versions by clicking File – View and restore previous versions.
Then the list of previous versions of the document opens.
Check out the Microsoft Support article View previous versions of Office files for more details.