N.I.E. (número de identidad de extranjero) is an identification number for foreigners in Spain. N.I.E. is one of the first documents any foreigner in Spain would need to identify themselves for officials or to open a bank account, forming a company, etc.
Foreigners that have an economic, professional or social connection with Spain may apply for an N.I.E. (art. 206 Regulation of Organic Law 47/2000, approved by Royal Decree 557/2011, of April.)
The N.I.E. could be applied for example assisted by a lawyer or personally at the Directorate-General of the Police (directly or through Spain's Consular Posts abroad).