Quick answer: use PennDOT Form MV-39 along with the assigned title and proof of death. A surviving spouse pays no title fee; a child or parent inheriting the car does.
One form, two paths depending on the will
A real fee difference for spouses
No title fee is required when the vehicle is being titled in the surviving spouse's name — a genuine cost savings compared to transferring the same car to a child or parent, which does require the standard title fee, plus any applicable sales tax and local use fee.
Proof of death has two acceptable forms
Either an original death certificate (copies aren't accepted) or the appropriate portion of Form MV-39 completed directly by the attending physician or funeral director satisfies the proof-of-death requirement.
A registration transfer fee applies separately
Beyond any title fee, a transfer fee applies to move a valid registration plate out of the deceased owner's name and into the new owner's name.
A local probate attorney can review your estate — many offer a free consultation.
PennDOT processes Form MV-39 the same way whether the vehicle is registered in Philadelphia, Allegheny, or any other Pennsylvania county.