Follow these steps to ensure the PO number is printed on the customer shipping label.
All orders shipped from a Game One Warehouse (using FDM4) will always have the Customer PO field generated on the shipping label (see picture below). This field is pulled from the data entered on the Order Information Screen or the Freight Tab. When the Customer PO # field is properly filled in on an order, then no further action is required. 
If the product is shipping from the manufacturer, putting the Customer PO # in the address field will give it the best chance of making it on the vendor's label since the customer address is passed over to the buyers when placing an order.
Follow these steps:
- With the order open, go to the Freight tab
- On the Ship To section, use the 2nd Address Line to put In the Customer PO Number.
- Click Save and be sure the "This Order Only" option is selected. (The screen defaults to that option automatically, although it can be hard to tell depending on your color scheme).
- Click Review and Complete to confirm the PO number is showing on the Ship To section.
My customer received a package and the PO number was not on the label. Why?
Despite our best efforts to communicate the necessary order information to our vendor partners, there are times when the information is simply not generated on the vendor's shipping labels. The vendor's system may not generate as many characters as ours, or it may have been human error.