Dear Befuddled,
They offer the forms like that as a convenience for their patients.
If it is not convenient for you, they will work with you.

I was at an office today with little tiny spaces and was wondering if it mattered what I wrote. I mean, if the space is too small for an ordinary address, maybe I can just use a made up version of my address and leave out most of it. Let's just make up stuff on those forms.

M.