A formal mechanism for defining a broad variety of postal products using measurable attributes. The mechanism for the products then may be formalized into data structures and procedures executable by computer systems. Once the above is executed an automated production is established for the mail unit and suitable for delivery of the new services to assist postal operators in effective execution of all operations specified by the services selected. In order to fulfill the mailer's requirement as expressed in computer processible format and captured by the mailer's computer the software may make decisions regarding the creation and sending of each mail unit. Based upon the mailer's requirements and available carrier services the mailer's computer may determine the need to modify the content of the mail units and create instructions or controls for the mail units.