A Schengen visa can be obtained from any of the Schengen Zone member countries. It entitles the holder to travel across the Schengen Zone. This also includes European Union Schengen members and EFTA Schengen members. This is subject to the validity and length constraints of the visa. It is always advised to find out who needs a Schengen visa before traveling.
There are differing restrictions that apply to each visa. This depends on the type of visa issued by a specific embassy or consulate of each Schengen country. It also depends on the nature of the trip and other relevant factors.
A Schengen Single Entry Visa allows its holder to enter the Schengen Zone only once. This is within the given period of time. As mentioned in the visa sticker affixed to their passport. Once the visa holder exits the Schengen territory, he or she can no longer go back, even if they have not spend there the number of days as permitted by the embassy that issued them the visa.
Some people confuse the single entry visa, thinking that it is about the number of countries the visa holder is permitted to visit, and that it allows them to enter one single country. In fact, the territory you are permitted to visit is given close to the “Valid for” tag in your visa sticker, whereas the time you are permitted to stay is given close to the “Number of entries” tag.
A Schengen Visa is a short-term European visa. This type of Visa enables the holder to travel freely throughout the Schengen Area. The visa, itself is issued by one of the Schengen nations. That is to say, you can visit any of the Schengen countries for up to 90 days during a 180-day period. The Schengen Visa is the most common visa in Europe. In order words, it entitles the holder to enter, travel freely within, and exit the Schengen area from any Schengen member country. There are no border controls within the Schengen Zone.