Format Requirements:

The CMRAs inform their customers, during the application process, regarding all the customer's responsibilities to continue or to start receiving mail services offered by the CMRA. The CMRA also provides its customer with the format to be used for the delivery of mail to the CMRA. If the CMRA customer refuses or fails to comply with Postal Service regulations governing the operations of a CMRA, the CMRA must terminate the relationship with the customers or deny the application of customers that refuse or fail to comply with regulations.

Source USPS