Is there a legal paper for a 18 year old to date a 16 year old?

Depending on what state you live in, you can date someone that age , you cannot have sexual contact with the person.

I live in Georgia and we don't want to have sex we just want to be together

What do their parents say as it's really up to them..

His don't care and mine are up my butt about it but we really love each other you were young but we really do

I would imagine yours are bothered for a reason. You should listen.
Teenagers, love and hormones generally have an effect that often ends in sex.
That is probably what your parents are worried about.