To load default jquery core file from CDN to WordPress, you need to simply copy and paste the following code in your theme’s functions.php file.
function replace_jquery() {
if (!is_admin()) {
wp_deregister_script('jquery');
wp_register_script('jquery', 'https://code.jquery.com/jquery-1.12.4.min.js', false, '1.12.4');
wp_enqueue_script('jquery');
}
}
add_action('init', 'replace_jquery');
Have any doubt, then comment here!