I would like to know the method of how to convert the signature to AS/400 object. Also, then use this object (signature)...
with the PRTF. When I print out the report (letter), the object has to adjust automatically with the length of the letter.
I assume you are asking about placing a "Signature" image on a printed document. If that is what you are asking, then the answers to all of your other questions are found in the same book The AFP Toolbox User's Guide.
In this book, you will find information on creating an overlay. Overlays can contain a mixture of text, image, graphics, and bar code data objects and also can include page segments. Unlike page segments, overlays contain all of the environment information required for their presentation. If you need an image that you can position within the overlay, then a Page Segment is your choice. There are also programming examples in C, C++, Cobol and in RPG.