Gather the paperwork you will need in order to become the executor of your relative's estate, such as the death certificate and will naming you as the executor.
Obtain a form for a Petition for Probate. Pennsylvania does not have an official, statewide form that you can use. However, the local county might have one you can use. If your county does not have one, adapt another county's form to your purpose.
Fill out the form for your petition according to the instructions.
File the petition for probate in your deceased relative's last county of residence. Along with the petition, you need to file the death certificate, will naming you as the executor and filing fee. The court will make an appointment for you to be sworn in as the personal representative.
Go to the probate court at the designated time of your appointment.
Ask the court to appoint you as the personal representative of your deceased relative's estate. You may need to show proof of identity. The probate court will give you letters testamentary that you can show third parties as proof of your status as personal representative.