Exclude content types from node search for Drupal 8.
Download and enable the search_exclude module.
- Go to /admin/config/search/pages.
- Find the 'Search pages' config.
- Create a new 'Content (exclude)' search page.
- Under 'Exclude content types', select the content types to exclude from the search index.
- Save.
- Disable the default Content search and make your new search page the default.