After you share a file, you can collaborate with others and work at the same time.
See who else is in the document and where they're working.
A presence indicator shows where someone is making changes. See any changes right as they're being made.
Add comments and @mention others to get input right where you want.
Note: Co-authoring works similarly in Word, Excel, and PowerPoint on Windows, Mac, and on the web.
Use Version History
With your file saved to OneDrive or SharePoint, use Version History to go back to a previous version of a file if someone makes a change you don't want.
Note: Besides a few differences, Version History works similarly in Word, Excel, and PowerPoint on the web and in the desktop apps.
Select the file name.
Select Version History.
Choose one of the versions.
Click through the Changes or scroll through the file to compare changes.
Select Restore to replace your file with the older version.
Collaborate on Word documents with real-time co-authoring
Restore a previous version of a file without unwanted changes