title_body: How to stamp text to PDF, with a twist The closest case I came across in this site is this question:
  How can I personalize each copy of a PDF to add the reader&#39;s name or email address to each page?
  
  However, I need something more advanced which is to add numbers to PDF containing gift vouchers. Here's what I want to do:
  
  
  Stamp the same PDF document with number, and save it with another filename.
  Each new PDF file will contain different numbers. BUT, all pages in
  1 PDF file contains the same number.
  The numbers will be placed at 12 different locations each page (some
  with different layout e.g text rotation), and repeated for all
  pages; except the last page.
  The last page of the document will be stamped with the same number,
  but only in 9 different positions.
  
  
  I managed to do the task using a PHP library SetaPDF-Stamper: http://www.setasign.com/products/setapdf-stamper/details/
  
  But I need something more automatic (and preferably cheaper), since I need to create hundreds of PDFs.
  
  I've been looking into various kind of PDF editor software (Windows applications), but they only support sequential and/or random numbering. While I need the same number to be stamped on the pages.
upvoted_answer: Maybe I don't understand the question, but if you can already do the job with SetaPDF-Stamper manually then all it takes is a little PHP code to do it automatically. There literally is no easier solution to your problem as described; to automate it will take custom code, period, and SetPDF-Stamper is the kind of library you would need for that purpose.