Help! modify child custody

My husband has primary physical custody of his two boys. He has an opportunity for a job promotion out of state. There is no agreement betweent the two as far as relocating. I know that we need to modify the custody agreement but not sure what steps we need to take. Also need child support help. He has had custody for almost two years and there is no support agreement. What steps do we need to take to start child support? Thank you for any help.

File an action for child custody and child support., your husband, as part of his case for custody will need to prove that moving the children will be in line with what is in their best interests.