1. Login to admin.
  2. Edit the page you want to update the page title.
  3. I.e. page title of the homepage
  4. Save.
  5. Open https://developers.facebook.com/tools/debug/sharing/ to check the facebook scraper.
  6. Paste the url you want to share.
  7. Click Debug.
  8. Scroll down to see all the details specially the og:title, og:image and og:description.