You pay road tax through the town hall where the car is registered. It is paid annually and to avoid forgetting it might be a good idea to set up a direct debit from your Spanish bank account. If you move, especially to an area that falls under a new town hall, then you should not only check with your insurance company any revised premium but also update the vehicle address. This can usually be done through the town hall. See u003ca href=u0022https://carinsurancespain.es/how-to-change-registered-address-of-vehicle-in-spain/u0022u003eHow to change registered address of vehicle in Spain.u003c/au003e