Long story short mother took off got pregnant, I been raising her, I just got full custody of my kids, biological father not in picture, and mother been out picture for a year.. I want to adopt before mother, ex wife comes back and tries to take her from me.. how do I adopt her to change last name.. been with her four years.. all she knows is me... birth certificate father says unknown. Single father and need some help.. thank you and be blessed..

Adoption cannot happen without either proving the biological parents a danger to the child and having their parental rights stripped, or by getting permission from the biological parents.

How are you making medical decisions for this child? Were you married at the time of the child's birth? If so, you may be the legal father, whether you are on the birth certificate. That depends on your state, though--where are you?

You generally cannot change a child's last name without BOTH parents giving permission.

Adoption cannot happen without either proving the biological parents a danger to the child and having their parental rights stripped, or by getting permission from the biological parents. ...

Or, in some states, if the non-consenting biological parent has abandoned the child. Thus one would have to know what state you are in and, in any event, you should talk to an attorney.