How to Add custom JS function into Adobe Campaign

For adding a document level JS see Action or Javascript to set a group of PDFs to open print dialog automatically

Is this about a PDF created by some consulting service?

If the PDF is not locked, you can use Acrobat to edit the PDF like anyother PDF. It is locked you need to contact the creator of the PDF.

This forum is about Acrobat JavaScript. Is Adobe Campaign a part of Acrobat?