Simply said, a visa is a ticket to a country.

A visa is a stamp or sticker in your passport and will be issued by an embassy, consular department or, in some countries, at arrival.

All visa have a certain validity.
With a visa you can enter the country (and leave it as well).

The number of entries is indicated on the visa.

There are different types of visa.
Every country has its own types and names.
Normally the names are: for tourists (Tourist), for business (Business), for students (Student or Study), for visiting relatives (Private), etc.

On this site, you will find information for all the visa of all countries.