How does my fiancée go about adopting my daughter. She has my last name and the father is not in the picture. There is no father listed on the birth certificate. He has never seen her and wants nothing to do with her. Does he still have rights? She is 4 years old

As long as the bio father will sign over his rights to allow the adoption. Since he is not listed on the birth certificate most likely you will have to get a DNA test to prove he is the father first.

Unfortunately, yes he does still have rights because he is the biological father. He will need to be found, and he'll need to sign over his parental rights to the child before anyone can adopt her. If he refuses to do this, then you cannot have anyone adopt her.
Most states require you to be married before the fiance/step father can adopt. Nearly all do from my knowledge, so you may be able to get the process started before the wedding, as we did, but it will not go to court and be final until after you are married.

Other than all of the above, have you ever thought what if you and your spouse are divorced after "your girl" became "our girl"... legally he has the rights and you will get stuck in custody battle especially if the divorce gets nasty...