Foreign nationals with a study permit who have been offered a job can obtain such a change of status without having to apply for a visa in their country. 

Requirements

• You must show that you have lived in Spain with a study permit for a continuous period of at least three years.
• You must prove that you have successfully completed your studies or research project.
• You must not have received a grant or subsidy from a public or private body form your country of origin as part of a cooperation or development programme.
• You must not have a criminal record in Spain or any other country in which you have previously lived.

Procedure

UPF's Teachinf and Research Staff Service will make an appointment for you to carry out the administrative procedure in person. 

Documents required:

• An EX-09 application form
• Your passport (original and a full copy)
• Your study permit (original and a copy)
• A certificate stating that you have successfully completed your studies
• A copy of your contract
• A document stating that you have not received a grant or subsidy from a public or private body from your country of origin as part of a cooperation or development programme. The document in question may be: 
  • A certificate from the Spanish Directorate-General for Consular Affairs and Assistance stating whether you showed that you had your own economic resources or a grant when applying for a visa.
  • A certificate from your country of origin's diplomatic mission or consular post stating that it is not possible to show that you have not received such a grant or subsidy, accompanied by a sworn statement from yourself that you have not received such funding.

Your application for this change of status must be made in the three months prior to the expiry of your study permit.

Once you have it, it must be necessary to apply for the TIE (foreign identification card). 

More information.