Miss: If you are an EU citizen:-
As you will see here:- https://www.gov.uk/guidance/residency-requirements-in-spain
If you come to Spain intending to stay for 3 months or more you must register on EU Citizen’s Register.
In your case as you do not have a job nor job offer you would need to prove medical cover, income etc. However, if you come to Spain as visitor ‘with the idea that you might seek work’ you will have 3 months grace. By doing that you will also be able to apply for an NIE should you wish to obtain one before you Register. In that case do not say you are seeking work, if you do you will not be allowed to apply for just an NIE. On the application you might say you wish to open a bank account, or buy a property etc. That would be sufficient reason to apply for an NIE.
When you get a job or a job offer, you will need to register on the EU Citizens Register but with the offer you will not need to have medical cover nor prove you have sufficient income.
Good luck.
PS if you are not an EU Citizen. If you provide more info I am sure you will get some helpful ,posts.
This message was last edited by johnzx on 13/03/2017.