To print a PDF, you can't use the .Net PrintDocument component according to my Googling. You'll need to use a third party assembly. This isn't really a Pega Robotics question though as that is really a programming task. If you'd like to interrogate the PDF reader application and automate the print steps through the application, then that would likely be possible using an adapter and the traditional automation methods. You might need to use SendKeys (control + P) to generate the print once the document is open, but I would try to automate the process like any other application first.