A system and method for the mass customization of bills or invoices particularized to each client's preference is provided. The present invention is used to permit a provider of mass customization billing service to customize invoice/bill formats, layouts, and contents for service organizations as well as recipients of those services. Under the system and method of the present art, the invoice generation process is driven by a set of format specifications customized to an individual account or client. Accordingly, the system and method of the invention is ideal for customers and clients that require particularized styles, formats, or information content relevant to invoices.