When approaching a jurisdiction to serve as Administrator or Executor of an estate, you will need to provide evidence that the person has passed away. This can be supplied in the form of a certified copy of a Death Certificate. This document can be obtained from the funeral home or directly from the state.
You will also need to bring along your driver's license or other form of ID, since you must show proof of your identity in order to apply to be an Executor or Administrator.
Finally, you will need a copy of the will naming you as the Executor. If you do not have this proof, you will have to provide evidence that you're the next of kin. If you are not the next of kin, you will be required to obtain consent from all other parties who are next of kin that they renounce their rights to be the Executor to you.