My wife and I live in az. Can I adopt her daughter who is now 8 and her father is not listed on birth certificate

They are going to need to know who. They will certainly not believe it was an immaculate conception.

Not without establishing who the father is legally and then getting his permission to adopt.

By leaving the father off, its now harder to do an adoption. The courts will require that all potential fathers be identified and tested. Only then can the adoption proceed.