How to Hide the "Simple Lazy Load Videos" Admin Menu

function plt_hide_simple_lazy_load_videos_menus() {
	//Hide the "Settings → Simple Lazy Load Videos" menu.
	remove_submenu_page('options-general.php', 'simple-lazy-load-videos');
}

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

Where do I put this code?