How to Hide the "Appmaker WP Settings" Admin Menu

function plt_hide_appmaker_wp_mobile_app_manager_menus() {
	//Hide the "Settings → Appmaker WP Settings" menu.
	remove_submenu_page('options-general.php', 'appmaker-wp-admin');
}

add_action('admin_menu', 'plt_hide_appmaker_wp_mobile_app_manager_menus', 11);

Where do I put this code?