Shippers want documents like commercial invoices, that list the country of origin of every item in the shipment, to appease the customs brokers and customs inspectors/officers. A royal pain for companies not used to shipping out of the US, or Canada and most other countries as well. These rules don't normally apply to shipments by individuals on shipments valued under $1000 or so depending on destination. BUT. Shipping documents by FedX ground to Canada from the US requires commercial invoices on private shipments only containing a passport renewal application.