What is a shipment reference?
A shipment reference is an identifier that you define by completing the “reference” fields during the shipping process. This reference could be a purchase order (PO) number, a customer number, a company name, a Bill of Lading number, or a phrase that identifies that shipment — such as “10 crates” or “gift for Mom.” Shipment references can be any combination of letters and numbers up to 35 characters.
