Adding text to existing PDF page

[dymatrix]

I am looking for assitance on how I can take an existing PDF form  and using  FreePascal/Lazarus    draw/write text  to fill out the form  , drop  text and logo somewhere and then combine a bunch of pages to make a document.   I have an old solution (no source ) that was created in Delphi  and it does just that.  I reads a CSV file, for which I know the layour and then will place the values at the appropriate coordinates on the pages and then assemble the pages into a single PDf doc.  I want to rewrite process using FreePascal and Lazarus to run on Linux 

I am looking for some guidance, a library and hopefully some examples.  I would even create a simple app that I can share back that does what I need done, except it would not include the forms I am using.

Hoping