Hi
do not get dishearted by various discussions about the latest regulations. You can rent houses, apartments and even offer shared accommodation.
The major exceptions to this are Europewide e.g. areas of high density of tourist accommodation offers (Barcelona Paris Berlin ....) can and will restrict new applications for rental in certain areas where it is deemed that an already scarce housing situation is amplified by usage of such for turists. Second here in Spain one has to read carfully the owners papers of multi apartment housing as some housing comunities do not allow usage for tourism, but this is clearly stated in the deeds that this property has restrictions.
The main issue is that this normativa is regulated on a regional level. E.G. Galicia where I sit has slightly different rules than for example Aragon.
The next issue is that one needs an "Informaion of intend to establish a business for the use of tourism" in form of the rental of a complete house, apartment or shared room - hand over keys no hotel services. This is an informal letter to the local council. They than have 20 days to answer. Some councils are organised and have some paperwork but the usual is "escritura / deeds" location and very important third party liability insurance of more than 300k €.
This can no longer stop you as it is in parallel with informing the local / regional tourist office and ask for the required paperwork. This is normally in form of a declaration of responsibility / intend "declaracion de responsibilidad" than one has to pay some on off taxes have the third party insurance, escritura / deeds maybe a copy of the NIE and a reasonable plan (outline) as well as a good description with acurate measurements.
The regional requirements vary from - yes - how big the beds have to be - to the bathrooms per pax and that an iron needs to be provided etc. just check locally.
A resource to explain as well is here https://cincodias.elpais.com/cincodias/2017/08/01/ahorros/1501569615_038303.html
Be absolutely clear that you rent out entirely for the whole year or part of the year and just hand over the keys - There is as of yet no VAT and no further business taxes nor is there a requirement to be self employed - any more will get you into the focus of VAT and hotel services, than you may be required to become selfemployed as well. If you are resident you have to declare any income from this above 1k € with your normal tax declaration - deductions apply as usual.
Whilst this process is on going and it can take a long time for an inspector to show up you can run this on a temp basis.
Please note I'm not a layer or taxman and can only speak with certanty for Galicia but I''m just registering my second house here and I dont take no for an answer.
You should know that your local council office (Ayuntamiento / Concello) is the registered post office for all paperwork.
They have to register any letter / paperwok to any government office including themselves, than send it to the apropriate office. They may charge a nominal fee for copies. This registration is very very important.
Hope it helps and do not take no for an answer here in Spain.
Martin GJ