How to exclude a part of a page in search results

Copy below code and paste in function.php file to exclude pages from search results.

if (!is_admin()) {
    function wpb_search_filter($query) {
        if ($query->is_search) {
            $query->set('post_type', 'post');
        }
        return $query;
    }
    add_filter('pre_get_posts','wpb_search_filter');
}