How do I stop Wordpress from duplicating content?

Preventing Duplicate URLs

  1. A page and a post should never share the same title.
  2. If you use the Duplicate Post plugin, always change the title and the URL of the Clone page to something unique.
  3. Only publish pages that you plan to use.
  4. Delete unused pages and drafts.

For More Information Please Refer: https://www.wpfixit.com/wordpress-duplicate-content-issues-and-how-to-fix-them/