I have a car my ex and I bought in PA it is paid off and I am back in ny. To sell or trade it do I need her signature as well
If the vehicle is jointly-owned according to the title, then you will have to secure her signature to be able to sell it. You cannot sell a jointly-owned car alone, unless the other person is deceased. Talk to the local DMV for advice.
If both names are on the title then yes she also needs to be present to sign title over to the purchaser. Unless you know a shady notary.