What is the law in AZ regarding moving out of state with a child age 15 when the other parent still lives in the state.

Generally speaking, if there are already orders in place regarding parenting time, then a parent must follow the provisions of ARS 25-408 and serve 60-days written notice upon the other party of the intention to move. The other party then has 30 days to ask the court to prevent the relocation and the court will decide whether it is in the child's best interests to relocate. This can be difficult to prove depending on the circumstances. There is more to the statute than what I've briefly described here, so I recommend you consult with an attorney prior to taking any action.