A Schengen visa is required when staying in the Schengen Area for up to 90 days.
A Schengen visa is granted in the form of a sticker affixed to the passport, travel document or other valid document that entitles the holder to cross the border between Schengen countries. Possession of a Schengen visa does not confer automatic right of entry. Entry will only be granted if the other conditions laid down by the Schengen Convention are met, i.e. the justification of the purpose and conditions of the trip, minimum amount of funds travelers must have at their disposal and the possession of valid travel insurance.
With a Schengen visa, you may enter one country and travel freely throughout the Schengen Area. It is issued to citizens of countries who are required to obtain a visa before entering the Schengen Area.
A Schengen visa allows the holder to travel freely within the Schengen Area for a maximum stay of up to 90 days in any 180 days period. If you wish to stay longer than 90 days you will need a national long stay visa or a residence permit.