What is a permit given by a country that allows someone to go to that country called?

A visa is a permit given by a country that allows someone to go to that country. A visa is a document that is stamped on a person's passport by an embassy. It names the kind of visit and says how long the person can stay. Sometimes, people need to go through an interview held at the embassy before they get a visa.

Some visas can be granted on arrival or by prior application at the country's embassy or consulate, or sometimes through a specialized travel agency with permission from the issuing country in the country of departure. If there is no embassy or consulate in one's home country, then one would have to travel to a third country (or apply by post) and try to get a visa issued there. A fee may be charged for issuing a visa.

Common types of visas are: a transit visa, a tourist visa, a business visa, a temporary worker visa, a spousal visa etc.

Visas can also be single-entry, which means the visa is cancelled as soon as the holder leaves the country, double-entry, or multiple-entry, permitting multiple entries into the country with the same visa.

In western Europe in the late 19th century and early 20th century, passports and visas were not generally necessary for moving from one country to another. The relatively high speed and large movements of people travelling by train would have caused bottlenecks if regular passport controls had been used. Passports and visas became usually necessary as travel documents only after World War I.