in this states there is a full service gas station or self?
Most petrol stations in the USA (including California) are self-serve. Self-serve means fewer employees to pay and more profit to the petrol station. The pumps are automated...you insert your debit or credit card at the pump, select the grade of fuel, and then fill the tank. If you'd rather pay cash, you first have to go inside the station and give your money to the cashier, then go back and fill your tank. Many stations also offer car washes, which are helpful when you've been on the road for a long time and your windshield gets dirty from the dead insects.
The only exceptions are Oregon and New Jersey, where it's actually illegal for drivers to fill their own cars.