Please see below some notes direct from the UK Embassy (UKINSPAIN)
https://www.gov.uk/living-in-spain click here
Registering on the padrón
The padrón is a list of all the people who live in a certain town. Empadronarse is the act of registering yourself on this list with your local town hall.
Who should register?
It is obligatory by Spanish law to register on the padrón at the Town Hall where you habitually reside, yet many British ex-pats still have not done so. Perhaps some view the padrón as a means of vigilance by the state, in ‘big-brother’ fashion. However, in reality, it is simply a way for the town hall to know how many people live in their area, without entering into investigations as to a person’s official residence status or financial affairs.
How you register
You don’t have to own your house to register, just have an address where you habitually live, no matter whether you are the owner, you rent, or live with family or friends. Nor is registration a long drawn out registration process. Simply go to the padrón office of your town hall and fill in the form they provide. Take along official identification, such as a passport, and also your NIE or residence certificate/card, a recent utility bill in your name, and the deeds to your house or a copy of your rental contract. Although you may have to return to collect your certificate, the actual registration is completed all on the same day. Some town halls in the Balearic Islands make a small charge for issuing a ´Certificado de empadronamiento’ (eg 1.20 euros in Palma de Mallorca).
Benefits of padrón registration
Once you’ve completed the simple process, you can begin to enjoy all the advantages being on the padrón offers, such as:
Better public services
Central government allocates money to the different municipalities according to how many people are on the padrón. Therefore, if you are not registered, your town hall is losing money for the provision of health centres, police officers, fire fighters and schools.
Access to benefits and social care
You must be on the padrón for a certain period of time in order to access some income-related benefits and other aspects of social care available through social services at your town hall.
A reduction in taxes
Depending on the town hall, registration on the padrón could mean reductions in certain community charges and inheritance tax. Furthermore, those on the padrón can also often enjoy discounted courses, leisure and cultural activities run by the town hall.
A current ‘Cerificado de Empadronamiento’ can allow residents of Spanish islands to receive discounts of up to 50% on air fares and ferry tickets between the islands and the mainland.
In order to register to vote in local or European elections, you must first be registered on the padrón.
An easier life
You’ll find you need your padrón certificate to carry out various administrative tasks, such as register for healthcare, register your car with Spanish number plates or enrol your children in school.
More information can be found on Ciudadanos Extranjeros website.
Padrón status checks
Our understanding from talking to local and national authorities is that there is currently a one-off exercise underway to check the accuracy of the padrón registers. This means you may be contacted to confirm your status on the padrón. If you are contacted, you will be asked to answer to remain active on the padrón and if you don’t then you may be removed from the register. If you are not contacted, you are not required to confirm your status.
For certain services (eg social services) you may be required to show a recent padrón certificate which is less than 3 months old. This is normal procedure and is not related to the above mentioned project.
Non-EU citizens are required to renew their padrón certificate in any case. Please contact your locality authority about any changes to the padrón registration process.