Does anyone know how I can add my child's dad on to her birth certificate?

How old is the child? Have you contacted the hospital or local bureau of records?

My child is 4 in April I have not contacted anyone yet just want to know where I should start

With the child that old, you may need to go to court to have this done. I would start with the local Bureau of Records. They should be able to tell you the process for you area.

OK thanks for your help and if any one else has any more info can you let me know please