Congrats on your approval.
I had my pp stamped recently, and I didn't fill in any form, though I saw the lady officer filling one in for me. It was a white form, and I was fingerprinted and also gave my signature on that form.
The situation varies across offices, though. I've read in some threads that applicants were asked to fill in some form at time of stamping (but I've never read anything about 20-30 questions).