https://www.webtoffee.com/add-product-description-in-woocommerce-invoice/
add_filter('wf_pklist_alter_product_name','wt_pklist_alter_product_name',10,5);
function wt_pklist_alter_product_name($order_item_name, $template_type, $_product, $order_item, $order)
{
return $order_item_name.'<br />'.$_product->get_short_description();
}
