How to Hide the "PDF Embedder" Admin Menu

function plt_hide_pdf_embedder_menus() {
	//Hide the "Settings → PDF Embedder" menu.
	remove_submenu_page('options-general.php', 'pdfemb_list_options');
}

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

Where do I put this code?