Wordpress Search Filtering

search_filter.php

  function prefix_search_filter($query) {
    //is_admin check prevents Search Archive in Dashboard from breaking

    if (!is_admin() && $query->is_search) {
      //Set the Query Options Here, e.g. $query->set('post_type', 'post');
    }
    return $query;
  }
  add_filter('pre_get_posts', 'prefix_search_filter');