I was wondering how to go about having the biological father of my 3 year old daughter to waive his parental rights so my current husband can adopt her. My daughter's biological father hasn't been in her life since the age of 8 months. I live in Massachusetts and he lives in Washington state, could you please tell me how to go about this and what paperwork I need to file, or can it be just a letter stating he gives up rights and has it notarized.

No, it has to be part of a formal adoption motion that is filed with the court. There is really no "fill in the blank" for this, you need to hire an attorney who will do the adoption paper work, do the forms for him to sign to give over his rights for the adoption.

His child support will continue till the paper work is formally accepted in court.