A system and method for preparing mail packages to be sent to recipients. The package includes a carrier envelope with a front address window and a back window. A content document having a style code printed on it is positioned at the back of the carrier envelope. The content style code is positioned to be visible through the back window of the carrier envelope. A reply envelope is enclosed with an address area aligned with the front window of the carrier envelope. Mail packages are prepared by storing a corresponding content style for the recipient. While transported, the content style code is scanned. From the style code, a recipient having the corresponding content style is selected from the stored list. That recipients name and address are printed onto the address area of the reply envelope through the address window on the front of the carrier envelope.