Updated documents in a SharePoint document library become new versions. The most recently edited version of a document is always the current version. You can view the history of changes for documents that synchronize with a SharePoint site.
Click the document for which you want to view version history.
On the Home tab, click Versions.
A Web browser opens and navigates to the version history page for the selected document on the SharePoint site.
For more information on using a version history in a SharePoint document library, see SharePoint help.