put (something) (down) on paper
To write or print something on physical paper. You should try to put your ideas on paper as they occur to you, or else you probably won't remember later. Let's put the pros and cons down on paper and decide whether it's worth going ahead with it. Put your appeal on paper, and we'll review it at our next board meeting.
put something on paper
Fig. to write something down. You have a great idea for a novel. Now put it on paper. I'm sorry, I can't discuss your offer until I see something in writing. Put it on paper, and then we'll talk.