Example: For one person of a couple owning a property to be able to sell the house with POA for the other, absent partner, you must obtain a POA in Spanish, with the apostille of The Hague (apostille not necessary when POA is drawn up in Spain). Must be a full POA, but also listing all the offices including tax agency that may have to be dealt with by the empowered person. Full passport and NIE copies of the empowered must be added to the POA. Best to have it drawn up by an experienced lawyer.