Basically, revisions and autosaves are a snapshot in time of your post, page, or custom post type content that make it easy to roll back changes when needed. Each time you save a draft or update, a revision is created and saved within your database.
Follow the steps below to access the revisions feature within you site:
Login to your WordPress Dashboard.
Edit the page or post you want to view revisions for.
Look for the Revisions link in the sidebar of the WordPress editor.
You can use the slider at the top to select different revisions and WordPress will compare the revision that you’ve selected with the revision that immediately precedes the revision that you’ve selected.
The changes in each revision will be highlighted in green (for additions) and red (for deletions):
When you view a given revision, it will show a comparison with the revision immediately previous to it.
If you don’t want to compare a revision with the revision immediately before it, you can also check the Compare any two revisions box to compare any two revisions against one another using the sliders:
There are two approaches in how to undo changes within the WordPress editor and restore a revision:
Full content restore.
Manually restore - Copy and paste.
Note that with selecting this option WordPress will completely replace the current content with the content in the revision. In order to keep the changes, you will need to save the draft, or Update the page.
In case you have deleted a single paragraph that you want to get back, but don’t want to overwrite all the other content you’ve added since then, you can use the manual copy and paste to do that.
You can copy parts of revisions that you would like to restore and click Return to editor link to close the window after that paste in the part of the revision into the editor.