I submitted everything to them in Word documents (one document per chapter). They converted those to PDFs after having applied a lot of formatting and illustra

I submitted everything to them in Word documents (one document per chapter). They converted those to PDFs after having applied a lot of formatting and illustrating and sent me back the PDFs to review. If I found any mistakes, I marked up the PDF and sent it back to be updated and re-reviewed. So probably a lot of Adobe software?