Yes, you need "a" before "paper."
The paper could be some kind of certificate (birth certificate, death certificate, stock certificate, etc.) or perhaps a will or some other type of legal document.
Thank you for your help.
Can a paper mean a piece of paper?
Yes, but if it's in a safe, it's probably not a blank piece of paper! It undoubtedly has legal or financial information on it; otherwise, there'd be no reason to keep it in a safe.
The paper has a drawing of Picasso's. In this case, isn't it a piece of paper with his drawing on it? When the piece of paper has a drawing on it, can we use 'a paper'?
If you refer to it as "a paper," the assumption will be that it's blank. If you want to be specific (which is always a good idea!), then you should indicate what the paper is -- that is, what it has on it.
In this case, you should call it "a sketch by Picasso" -- and people will know it's on paper.
I am in 2nd grade.I no what your talking about.