There are 2 ways of viewing the version history of a document – In SharePoint or in Word/Excel.
The SharePoint method – will let you view a list of the changes made to the document but you will not be able to view the earlier versions of the document.
Word or Excel method – will allow you to view and compare earlier versions of the document to see and compare changes.
SharePoint method
View Versions
- Select the file.
- Click the Ellipses next to the file or on the ribbon then select Version History. The Version history will display:
- Click on the date/time hyperlink of the version you wish to view.
Restore a Version
- Select the file.
Click the Ellipses
next to the file or 
on the ribbon then select Version History. 1. Click on the drop down to the right of the version you wish to delete.
Click Delete.
Deleted versions go to the recycle bin (with their version number) and can be restored from the recycle bin. They are automatically restored back into the correct position in the Version history list.
If you have approved documents turned on, you will see Reject this version instead of Delete.