At the end of this post, you will see how to you will know how to view or restore a past version in Google Docs
In the past, you might have done multiple changes to your files. In case you needed to refer or switch to earlier versions. Google Drive keeps all your changes in one file. You can easily view, revert back or restore past versions.
For example you can:
View, delete, download, or revert back to previous versions any time
You can access any version of your file anytime, from any device
Also, refer back to existing comments in a previous version
Keep your folders clean and there’s no need to keep multiple drafts of your files anymore
How to view or restore a past version in Google Docs, Sheets, and Slides files
Note: Keep in mind that you need Owner or Editor access to see the version history.