We are happy to reference a PO number on a pro-forma invoice or invoice. However, we do not send back signed acceptance of purchase orders. This is because the terms and conditions commonly associated with purchase orders often contradict the terms and conditions of our offer. Our standard terms and conditions have been carefully authored to be fair to both our customers and us.
Also, note that we do not consider receipt of a purchase order as acceptance of our offer. To accept a quotation that was sent to you manually, we require you to send back scan of signed acceptance of our quote.
To have the PO number included in invoices for online orders, you need to input the PO number in the final step of the purchase process. The PO number will be mentioned in the automatically generated invoice.