This will depend on the carrier for this shipment. In some cases, carriers will send the necessary customs forms for an international shipment back to your ShipStation account along with the label so you can print them out. For some carriers, customs forms are submitted electronically by ShipStation, and so do not need to be printed at all.
In a few cases, as with Royal Mail, customs forms must be created outside of ShipStation.
For details on your specific carrier and how customs forms are managed, review your carrier's integration page in our Integration Help guide.
USPS international shipments use integrated labels if a separate customs form is not required. Integrated labels display the customs information directly on a single label. These labels are transmitted to ShipStation from the postage provider already formatted with the fields and information required by the carrier, and there is no need to print additional forms for these packages.
Basically, you'll see two types of integrated customs labels:
A single-part label (a.k.k "single ply")
A three-part label (1 - Proof of Payment, 2 - Customs Declaration, 3 - Dispatch Note)
The single-part label is easy to use - it's like any other shipping label.
ShipStation doesn't control which international shipments get the single-part labels and which get the three-part labels. The USPS postage providers determines this according to USPS requirements (e.g. declared value and destination country), which are subject to change.
For example, USPS recently decided that shipments to Australia, Canada, Costa Rica, and US Military destinations no longer require three-part labels (see Appendix D of this USPS document).
The three-part label requires you to put the labels, in order, inside a USPS-provided window pocket. These window pockets are free and can be ordered from your local post office or from the USPS website.
For more information on shipping internationally, review the International Shipping section of our help guide.
At this time, ShipStation does not print NAFTA forms. If you require a NAFTA form for your international shipment, you will need to create it outside of ShipStation.
You can learn more about NAFTA and its customs requirements on the U.S. Customs and Border Protection website.