The days of the plain old invoice are gone. Today’s customers can be very demanding when it comes to the invoices they receive. And let’s face it they have a reasonable amount of clout when it comes to getting their demands met. Delaying payment can be a great motivator to giving the customer what they want.
Ideally then vendors should agree with the customer up front as part of the sales process any specific requirements they have for invoicing. This will allow time for the vendor to ensure that the invoice process and more importantly payments are not held up due to problems meeting these requirements.