The terminal on the pump will ask for a zipcode. If you can't pay at the pump (which sometimes happens even for locals for no apparent reason), you can step out

The terminal on the pump will ask for a zipcode. If you can't pay at the pump (which sometimes happens even for locals for no apparent reason), you can step out of the car, go inside, and tell the cashier which pump you are at, and pay as if you were buying any other product.