About Tax Identification Number (Spain's Número de Identificación Fiscal, NIF)
or Foreign Identification Number (Spain's Número de Identificación de Extranjeror, NIE):
The applicable Spanish legislation currently requires that any individual
or legal entity with economic or professional interests in Spain,
or involved in a relevant way for tax purposes,
must hold a tax identification number (in the case of legal entities)
or a foreigner identity number (for individuals).