Assume all of these are happening
You are in the accounting (specifically Accounts Payable) department of your firm. You handle approving payments made to vendors.
Your standard process assumes that internally your operations department has requested and approved permission to order some specific product or service at a certain price in a certain quantity.
Your procurement department found an approved vendor to provide that product or service as specified.
Your internal document trail has:
The original request with authorizations
The executive management approval
The procurement approval and selected vendor
The purchase order number for the contract / purchase agreement with the vendor
The vendor's acceptance of the order and their payment terms
The vendor has documents proving the manufacture and shipment of your order
The shipping firm (if not their own) has documents for the receipt of the product from the vendor and transportation to your facility
Your receiving dock has documents noting the date, time, quantity, and acceptable quality of the product being received
You have access to all of your internal documentation
Determine whether you would or would not support working with sophisticated vendors (ones that meet the assumptions above just as your company meets the assumptions above) to develop an ongoing process so that (1) they would not have to generate invoices and (2) you would not need to process their invoices - but you would authorize payment to them upon receipt of the material or service. ("No invoices" means no paper or electronic invoices.)
If implemented, both parties save significant time in their accounting departments. Do not document this new process in detail - discuss why you would not support it or why you would. You do not need to have references, but you can if they help the reader.
Include legal (US-based), auditing, control, finance, warehouse, procurement, and any other dimensions to your discussion. Include any issues that might need to be worked out if you do decide to implement such a process. Know what information is and is not on a typical invoice (don't embarrass yourself).