I'm guessing the file is supposed to be some kind of machine readable packing slip (customer and product information, quantities etc.) to be sent to the supplier's system for processing.
I have done a few things similar enough to adapt to your needs. All I need is the specification of the desired format, and possibly what to do with the file. (Presumably upload it somewhere. I would expect the PDFs to be emailed, which seems like a somewhat roundabout way of transferring data for automated processing.)