Hi
@LD_specialistIt is stored in SharePoint
In the File tab, you should see a menu item called Open in SharePoint, if you click that you will go through to the underlying Sharepoint Site. This is used for documents that people collaborate on together. The department handbook is a good example of a document which would up in the Teams file tab, and to which people can see and work on together.
Personal files, those you share 1:1 would go in OneDrive. OneDrive is a part of SharePoint but is a seperate service for personal files
Teams sits on top of both SharePoint and OneDrive so you can access both files that multiple people work with and collaborate on (SharePoint) and your own personal files (OneDrive)
Versioning can be enabled in SharePoint - see here
https://support.office.com/en-us/article/Enable-and-configure-versioning-for-a-list-or-library-1555D...Hope that answers your question
Best, Chris