All you need is your Identification Card, or a valid passport. Minors travelling with their ID card must have a document that shows parental authorisation.
If you are from any of the following countries: Andorra, Argentina, Australia,
Bolivia, Brazil, Brunei, Bulgaria, Canada, Chile, Costa Rica, Croatia, Ecuador,
El Salvador, Guatemala, Honduras, Israel, Japan, Malaysia, Mexico, Monaco,
Nicaragua, New Zealand, Panama, Paraguay, Korea, Romania, San Marino, the Holy See,
Singapore, United States of America, Uruguay or Venezuela, as well as the Special
Chinese Administrative Regions of Macao, and Hong Kong:
All you need is a valid passport to enter Spain, where you can stay for a maximum of 90 days.If you are from any other country, according to EU criteria: You must request a visa at the Spanish Consulate in your country of residence. You will also need a valid passport. Link to Spanish embassies & consulates