The Revisions ability shows any backup copies of your Page or Post. Each time you click Save Draft or Update Post, a version is saved. Revisions allow you to look back at the recent changes you’ve made and revert to an earlier version if you need to.
To find the Revisions area, you will need to go to the edit screen for the blog post or page that you want to see the revisions for and scroll to the bottom of the page.
If Revisions are not visible, click Screen Options at the top right of the page and select “Revisions.”
To compare Post Revisions, select a revision date in the Post Revisions section under the text editor. Select another date in the revisions list, click Compare Revisions, and you can check out the two versions of your post side by side, with changes clearly highlighted. In this example, we’re comparing two versions of the same post, edited within the same minute.
To restore a previous version of a post, click Restore for that date and the post is reverted back