Am I the "witness"? Insurance claim Legal advice?

I was in an accident, and my car was a total loss. I was parked and outside the car. The guy didn't have insurance, but I had uninsured motorist and my insurance company is going to pay me for the car. They sent me a form (release in full of all claims and rights) Basically to not come after them for more expenses after I sign, but there are only two lines to sign... One says "witness" and the other "notary". There is not place for me to sign or am I supposed to sign where it says "witness"? The notary would not notarize it because of this. Very confusing.. Thanks