When setting up a business in Spain, you need to obtain an NIE number (número de identificación de extranjeros). This identification number is compulsory for foreigners who wish to set up a business or move to Spain. You need the NIE to rent accommodation, obtain a social security number, open a bank account, enrol in a school, pay taxes, etc. You will have to apply for it at the local police station in the city where you wish to settle.