Document history is a feature that allows you to see the history of edits for an article - not just the last edit - and restore it to any version.
When you revert to a version of the document, we'll keep the history, and the version you selected will be the new document.
Each change you make to a document, we autosave it for you, which will provide the version of the document.
To open Document History, click on the Document Settings - the 3 dots on the top right corner.
A new window will open, and on the left side, you will have the revisions. In the center, you will see the content of the document.
On the top right corner, you have the Highlight changes toggle to show the changes. The highlight is a comparison with the previous version of the document.