How to fix WordPress Website showing Unknown results in Google?

Solution:1

You need to check the Google Search Console. Some of the URL indexed by Google is a 404 URL, so manually check for the URL from Google Search Console, remove the indexed URL which are a 404 URL.

https://search.google.com/search-console/about

Solution:2

  1. Install Yoast SEO plugin
  2. Add metadata with Yoast.
  3. Create a XML site map
  4. Submit your site map at google console