Does the air of the fan in the interior of the car comes from outside air or is it the same air that circulate inside, when the air conditioner is off and heat is also off (just the fan) ? or is it an option available in all vehicles to choose between the 2 options ?
By default most cars have an outside air inlet which supplies fresh air to the passenger compartment. There is usually a control on the HVAC panel that allows you to select air recirculation which closes the outside air inlet and just reuses the existing air.
Usually you won't want to do this for very long as moisture quickly accumulates and will fog your windows.