The Portuguese Tax Card is issued by the authorities when an individual obtains their permanent NIF (Número de Identificação Fiscal/Número de contribuinte) number. Its size is as small as a credit card, and it includes the individual’s unique NIF number, the issue date, and the issuing regional tax authority’s name. On the other hand, you can find the NIF number on any document -regarding legal activities- such as on tax cards or on the citizen ID card, and the number is used in all correspondence between the individual and the tax authority of Portugal.