You're looking for information on Quite Imposing Plus 5, a popular software for imposing and arranging pages in the printing industry. Specifically, you're interested in the serial number and private code, as well as an interesting article related to the topic.
: Perform "mail merge" style operations, adding unique text blocks (e.g., serial numbers or codes) from a spreadsheet or CSV directly onto a PDF layout. Complex Shuffling quite imposing plus 5 serial and private code work
When you purchase a legitimate license: