When shipping internationally via USPS, a Commercial Invoice is a required document for all shipments booked. The below document will walk you through the process of creating a Commercial Invoice for a USPS shipment.
To begin, create an international shipment from the US to a country outside the US.
Click the Ship tab.
Select the order from your orders list or create a single shipment by filling in the Receiver Address.
After entering the international destination of the shipment, the international service options will be displayed. Select the appropriate USPS International Service, package, details, and content.
To complete the process, the only other information that is required is the commodity information including the Description, Unit Value, and Quantity. Complete the info in the highlighted and applicable boxes, then proceed to book your shipment. For more details on the definitions for each field visit the Help Center article: How to Complete an International Shipment Including a Commercial Invoice