NIF (Número de Identificação Fiscal), Portugal

The tax authority's leaflet for foreign citizens says registration as a taxpayer means obtaining a NIF, and that the number is an essential condition for many everyday acts, not only tax, including employment, contracts, bank accounts and social security. A personal NIF has nine digits, the first eight sequential and the last a check digit, and stays the same whether you are registered as resident or non-resident.

gov.pt explains that people with a Portuguese Cartão de Cidadão receive a NIF automatically; everyone else, Portuguese or foreign, resident or not, can ask for one at any time.

• Registration. The Ordem dos Médicos asks for your taxpayer card among the documents for inscription, which leads to your cédula profissional.
• Residence. AIMA asks for proof of tax registration with an application for a residence permit for employment. See AIMA residence permit.
• Work and everyday life. Employment contracts, a Portuguese bank account and a rental contract all need it.

1. In person: book an appointment at a tax office (Serviço de Finanças) or Loja do Cidadão through the Portal das Finanças, choosing the option for a NIF request by people without a Cartão de Cidadão, or by calling +351 217 206 707. Bring a valid passport and proof of your address abroad if the passport does not show it. Third-country nationals applying in person need a visa in the passport unless an exception applies.
2. Online: a legal representative (not the same as a tax representative) can apply for you through the Portal das Finanças e-balcão, under Registo Contribuinte, Identific, Atrib/Alter NIF-Singulares, attaching your passport, proof of foreign address, their own identity document and a power of attorney.
3. Through a representative in person, with a power of attorney. Powers given to a lawyer or solicitor do not need signature recognition.

Documents in a foreign language need a certified translation.

You do not need a tax representative just to obtain a NIF. The leaflet says that once you have a tax relationship in Portugal, which includes signing an employment contract to work there, a non-resident must within 15 days either appoint a tax representative in Portugal or sign up to electronic notifications from the tax authority. This is optional for residents of EU countries, Norway, Iceland and Liechtenstein.

A NIF obtained from abroad is registered with your foreign address. When you become tax resident in Portugal, for example by living there more than 183 days in a year or having your main job there, you must change your address to Portugal.

• Forgetting to update your address after the move, which leaves you registered as non-resident.
• Confusing the NIF with the NISS. The NISS is your social security number, a separate registration that AIMA also asks for.
• Costs. gov.pt says the request is free for Cartão de Cidadão holders but may have costs in other cases, for example when made through a tax representative.