What is the role of the king, socially or politically, in Spain?
Recently Spain's monarch abdicated his throne for his son. See info
Spain has a constitutional monarchy. The term "constitutional monarchy" means that the king is stripped from the conventional powers -though he retains very limited power- an absolute king would have. This contradicts the term absolute monarchy where the king is the de facto ruler - Qatar and Saudi Arabia, for instance, are absolute monarchies.
That being said, the King holds no political power nor does he interfere with the government (appointing executives, increasing taxes...). He and the monarchy serve as mere figures of State and many people see them as symbol of unity and culture in Spain. Subsequently, the existence of a monarchy in Spain and its evolution to what it is now -Unlike France or Germany- can be understood through the country's history.
This is pretty much equivalent to the British monarchy in the United Kingdom where the Queen has relatively small powers. The queen is the figurative head of the United Kingdom and the Commonwealth states. This also applies to the Nordic countries where monarchies are still preserved.
Hope this answers your question.
Kings Functions, established in the constitution:
1º Sanction and promulgate the laws.
2º To summon and dissolve the Parliament and call elections.
3º Call for a referendum.
4º Be informed about matters of state and, if necessary, to chair the Council of Ministers.
5º Propose and, where appropriate, to appoint the Prime Minister.
6º Appoint and dismiss members of the Government.
7º Issue royal decrees , granting civil and military positions and honors and awards.
8º Exercise the right of pardon under the law , which may not grant general pardons.
9º Hold the supreme command of the armed forces.
10º To hold the High Patronage of the Royal Academies.
The candidates to be prime minister are the chosen ones of the political parties. He presents as the leader of the party to the elections. Once, the elections are done it, the most voted leader needs the support of the absolute majority of the Parliament. If the leader is supported with the necessary majority, he presents himself to the king as a Prime Minister, and has to swear to the constitution.
"El Rey sancionará en el plazo de quince días las leyes aprobadas por las Cortes Generales, y las promulgará y ordenará su inmediata publicación."
It is the king's duty to sanction and promulgate the laws. He can't oppose.
To summarize in simplicity,
Yes he has a lot of power. The king is the head of Spain and could ultimately make most decisions for the country. He is the leader of Spain. That's not in question. He's not just a figurehead.
He doesn't usually interfere because there's no reason to as long as the government is running smoothly. His powers are mostly like a back up plan incase the government becomes less stable or there's an issue that the current government can't resolve.
I hope this answers your question enough. I tried to make it easier to understand.
The King of Spain has the power to make laws, change the constitution, declare war, hire or fire people in the government, host executions, and hold political events. The Queen of Spain has the power to send people in exile, hoist the Spanish calendar, and divorce the King. The Queen is indeed more powerful than the King as she can swap him out of office anytime she wants.
With the Queen of the UK she still holds all power she, allows her ministers to use them on her behalf. The name CONSTITIONAL does not mean strip of power, I believe Spanish king can make laws. But his prime minister has to also sign, this is not the case in the UK the Queen can do laws in council. The UK is part democratic on the wishes of the queen, I say part because she is not elected. Spanish monarch does have emergency powers or he could get rid of the of the constitution. In the UK the queen has the last say not only is she, able veto laws. But what parliament and her government do. When a government in the UK does a u turn now you know why. The Queen sits on the most powerful throne in the world. I studied the monarchy for eleven years, I have learnt a lot from doing so.