Go to the document library settings and open 'Versioning Settings'. Here you can chose to create major and minor (draft) versions on each edit. Plus, 'Require Check out' before document can be edited. In this way, when you save the document after edit, a minor version will be created, like 1.1, and when you publish your changes then only the major version will change, i.e. to 2.0.
Uploaded a file, checked it in, published, which created version 1.0
Now, Checked out the same file and edited in Word Online, which created version 1.1
now, checked in the file:
Now, published the file. Version history shows the major version is updated to 2.0