Hello Amber,
My name is Ali and I have a listed property on Airbnb in Andalucia (Mijas, near Malaga).
In order to start renting your property for short term (vacation) rental you need to get a license for your property and that is done through hiring an architect to visit and evaluate your property for suitability for rental. This process can take about a month or two. The architect will do all the paperworks and submits it to the Andalucia authorities.
You will receive a licence number for your property afterwards. Then you have to register your property with the Guardia Civil (Police) and you need to report your guests' traveling document information each time you host them.
The licensing of your property could run anywhere from 4000-5000 euros (depending on the architect and the juristiction where your property is in).
This is the best information I have for you for now. If you need additional info, please let me know and I can invetigate it more for you.
Kind regards,
Ali