The Constitution of Portugal, in its article 35, expressly prohibits the assignment of a single national number to citizens. This prohibition is related to the protection of rights, freedoms and guarantees. As such, a national identification number does not exist, but instead, each citizen has several different identification numbers to use for different purposes.

The main existing identification numbers are:

Civil identification number (NIC), also informally known as the B.I. (the acronym of the old civil identification document);
Tax identification number (TIN), also known informally as a taxpayer number;
Social Security number;
Health user number;
Voter number;
Driving license number.

The recognition in Portugal of higher education degrees and diplomas granted by foreign institutions of higher education has been regulated, since January 1, 2019, by Decree-Law no. 66/2018. This decree-law repeals the previous two on these issues, Decree-Law no. 283/83 and Decree-Law no. 341/2007.

Under EU social security legislation, nationals of the 27 EU member states, Iceland, Liechtenstein, Norway and Switzerland enjoy the same benefits as Portuguese citizens in terms of access to free or low-cost healthcare . To benefit from these services, citizens in the category mentioned above need to present the EHIC (European Health Insurance Card).

As a general rule, the documents required for student visa applications for entry into Portugal are:
Passport or other travel document (expiration date not less than three months after the visa)
Three passport-sized photos
Criminal record
Health insurance certificate
Academic enrollment document
Vaccine card
Academic qualification document (certified by the local Portuguese Embassy / Consulate)