To use versioning in Word, you need to store your documents in either OneDrive or in a SharePoint Library.
When documents are stored online, you can turn on AutoSave to automatically save as your work. You can also share documents by inviting someone to the library, or providing a link rather than sending a discrete copy of the document. Lastly, you can work with others to co-author a document at the same time.
For more information on saving to OneDrive or SharePoint, coauthoring, or using AutoSave, see:
OneDrive and SharePoint
Coauthoring and AutoSave