How to Hide the "Allowed Domains" Admin Menu

function plt_hide_page_authority_allowed_domains_menus() {
	//Hide the "Users → Allowed Domains" menu.
	remove_submenu_page('users.php', 'pageauth-settings');
}

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

Where do I put this code?