What goes in the box
Order fulfillment documents
Two documents the mill will print: a packing slip and an invoice. That is the fulfillment-document set.
Order fulfillment documents, here, are the PDFs a warehouse or shop attaches to a shipment. Slipmill does not generate pick lists as a third template. It does not generate postage.
Start with packing-slip. Add invoice when you bill on paper. Both take JSON. Both return application/pdf.
If you need a customs commercial invoice, look elsewhere. We print what you send; we do not file with a broker.