A visa is a document that a document requirred by some foreign countries if you want to get in.
The visa is issued by the diplomatic offices, (consulates, Embassies) and sometimes by the military authorities of a country.
It often takes the form of a sticker or stamp on the passport.
The visa usually indicates:
a date of issue
the length of the stay (a few days to several months or years, or indefinitely in cases of long-stay visa)
duration of use : period during which the visa can be used
The competent authorities may refuse an entry visa to a foreigner that seems to present a risk of illegal immigration or a threat to national security.
We can deal with visa, residence permits for companies.