When the picture for your ID or drivers license is taken, the lady/man that takes your picture, asks you, do you want to register to vote? If you say yes, they ask which party, then they do whatever they do and print out your new ID/drivers license.
The after a few days (I don't recall how many) the ID/drivers license applicant receives in the mail, a voter registration card, from >>> the voter registrars office <<<<< !!
Again, have you ever, been to Pennsylvania, or any other state in the United States and applied for an ID/drivers license? Yes? No?