How to Hide the "Webyx FG Settings" Admin Menu

function plt_hide_webyx_menus() {
	//Hide the "Settings → Webyx FG Settings" menu.
	remove_submenu_page('options-general.php', 'webyx_fg_plugin_settings');
}

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

Where do I put this code?