How can I sell a car that’s still financed?

Your lien holder should give you a "certificate of title" that the buyer can use to put tags on the car until you have the clear title issued after it's been paid off. Most loan originators try to get all this done within 30 days of your selling the car, just make sure the buyer knows this when you agree to sell it to them. This is assuming your loan is not with some local bank (if that's the case just take it there to complete sale) - if you loan is with some out of state entity then follow the above.