Include only specific post types in search results. The following will only include post and product post types in search results. Feel free to add remove your own post type names (coma separeated)

modify_search_query.php

<?php 
function SearchFilter( $query ) {

  if ( !is_admin() && $query->is_main_query() ) {
    if ($query->is_search) {
      $query->set('post_type', array( 'post', 'product' ) );
    }
  }

return $query;
}
add_filter('pre_get_posts','SearchFilter');