However, it is recommended that you create a child theme and paste the code into the function.php file of the child theme instead. This is to avoid breaking anything on your website when you try to edit the original theme. Furthermore, if you update the original theme in the future, your code will remain intact in the child theme. If you paste the code in the original theme, it might be overwritten whenever you update it.

If you do not know how to create a child theme, don’t worry. Watch the video below and follow it step-by-step.

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');
}