The word "signature" means "signature, signature, signature", which is more suitable for business occasions, such as signing a contract.

If you want to sign a celebrity star, you'd better use the word personally, which means "personally" and is usually used in such occasions.

So your sentence should be translated into:

Can you sign it for me?

May I have your autograph?

It is appropriate to choose different words to express in different occasions.

For reference only.