Just as in many other countries, Spain maintains a list of those jobs for which it is difficult to find employees in Spain, or the EU, and therefore maintain a national list of jobs which employers may advertise and fill the positions from outside the EU.
Should you have received an offer of such employment you must apply for the appropriate work visa.
Alternatively, an EU scheme – known as the EU Blue Card – permits those with sufficiently advanced academic qualifications or work experience to apply for and receive a visa permitting them to live and work in Spain.
A firm offer of employment is also a requirement. Other limitations include the fact that the salary offered must be a minimum of 1.5 x average salary.