A Social Security affiliation number (número d'afiliació a la seguretat social) is necessary to be able to do an internship in Spain.
Where can I get the social security affiliation number?
At any TGSS (Tesorería General de la Seguridad Social) office.
Here is a list of social security offices in Catalonia.
The following documents must be presented:
· passport + photocopy
· express authorisation of empadronament
· a white piece of paper with the NIE for students + photocopy
· completed Modelo TA1 form
· training agreement
· acceptance letter