General Visa Information
The word visa comes from the Latin “charta visa,, which means paper that has been seen. In other word it can be define as an indication that a person who required the visa is authorized to enter the country which "issued" the visa, subject to permission of an immigration official at the time of actual entry. The authorization may be a document, but more commonly it is a stamp endorsed in the applicant's passport.

Some countries do not require a visa in some situations, such as a result of reciprocal treaty arrangements. The country issuing the visa typically attaches various conditions to the visa, such as the time that the visa is valid, the period that the person may stay in the country, whether the visa is valid for more than one visit, etc. The possession of a visa is not in itself a guarantee of entry into the country that issued it, and a visa can be revoked at any time.
Visas are associated with the request for permission to enter (or exit) a country, and are thus, for some countries, distinct from actual formal permission for an alien to enter and remain in the country. Some countries require that their citizens, and sometimes foreign travelers, obtain an exit visa in order to be allowed to leave the country.

There are different types of visa issues in the world. The information about visa in the world is changed with the change of country because every country has different rules about the visa. For example in European Visa Information System (VIS) will be a database of fingerprints and facial scans consisting of all applicants for an entry visa into the Schengen group countries.
The Schengen goup means Schengen Agreement which established in a treaty signed between five of the ten member states of the European Community in 1985. So, this Schengen group established in 1985. It was supplemented by the Convention implementing the Schengen Agreement some five years later. It provided for the removal of systematic border controls between the participating countries.

The visa systems were established in June 2004 by the Council decision. The visa system is currently in the testing and this visa system will be launched for four years to test. But it expend for December 21 2009.