A visa (from the Latin charta visa, lit. "paper that has been seen") is a conditional authorization given by a competent authority of a country for a person who is not a citizen of that country to enter its territory and to remain there for a limited duration. Each country typically attaches various conditions to their visas, such as duration of stay, the territory covered by the visa, dates of validity, whether the visa is valid for more than one visit, etc. Visas are associated with the request for permission to enter a country, and are thus, for some countries, distinct from actual formal permission for an alien to enter and remain in the country. In any event, a visa is subject to permission of an immigration official at the time of actual entry, and can be revoked at any time.
The visa is commonly a stamp endorsed in the applicant's passport or other travel document. The visa, when required, was historically granted by an immigration official on a visitor's arrival at the frontiers of a country, but increasingly today a traveler wishing to enter another country must apply in advance for a visa, sometimes in person at a consular office, by mail or over the internet. The actual visa may still be an endorsement in the passport or may take the form of a document or an electronic record of the authorisation, which the applicant can print before leaving home and produce on entry to the host country. Some countries do not require visas for short visits.Some countries require that their citizens, as well as foreign travelers, obtain an "exit visa" to be allowed to leave the country.
A visa generally gives non-citizens clearance to enter a country and to remain there within specified constraints, such as a time frame for entry, a limit on the time spent in the country, and a prohibition against employment. Some countries do not require a visa in some situations, such as a result of reciprocal treaty arrangements. 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.
A visa application in advance of arrival gives the country a chance to consider the applicant's circumstance, such as financial security, reason for applying, and details of previous visits to the country. A visitor may also be required to undergo and pass security and/or health checks upon arrival at the border.
General Information
Some visas can be granted on arrival or by prior application at the country's embassy or consulate, or through a private visa service specialized in the issuance of international travel documents. These agencies are authorized by the foreign authority, embassy, or consulate to represent international travelers who are unable or unwilling to travel to the embassy and apply in person. Private visa and passport services collect an additional fee for verifying customer applications, supporting documents, and submitting them to the appropriate authority. If there is no embassy or consulate in one's home country, then one would have to travel to a third country (or apply by post) and try to get a visa issued there. The need or absence of need of a visa generally depends on the citizenship of the applicant, the intended duration of the stay, and the activities that the applicant may wish to undertake in the country he visits; these may delineate different formal categories of visas, with different issue conditions.
Some countries apply the principle of reciprocity in their visa policy. A country's visa policy is called reciprocal if it imposes visa requirement against citizens of all the countries which impose visa requirements against its own citizens. The opposite is rarely true: a country rarely lifts visa requirements against citizens of all the countries which also lift visa requirements against its own citizens, unless a prior bilateral agreement has been made.
A fee may be charged for issuing a visa; these are often also reciprocal, so if country A charges country B's citizens US$50 for a visa, country B will often also charge the same amount for country A's visitors. The fee charged may also be at the discretion of each embassy. A similar reciprocity often applies to the duration of the visa (the period in which one is permitted to request entry of the country) and the amount of entries one can attempt with the visa. Expedited processing of the visa application for some countries will generally incur additional charges.
...........................................................................................................................................
Countries that issue visas or permits on arrival as a general rule for all arriving visitors
Countries that issue visas to a select group of nationalities (more than 10)
This reciprocal fee has gained prominence in recent years with resentment by some countries of the United States charging nationals of various countries a visa processing fee ($140 for tourist visas, non-refundable, even if a visa is not issued). A number of countries, including Brazil, Chile and Turkey have reciprocated. Brazil requires an advance visa before entry into the country, and that a US citizen be fingerprinted and photographed on arrival—matching U.S. requirements for Brazilians and other foreigners.
The issuing authority, usually a branch of the country's foreign ministry or department (e.g. U.S. State Department), and typically consular affairs officers, may request appropriate documentation from the applicant. This may include proof that the applicant is able to support himself in the host country (lodging, food), proof that the person hosting the applicant in his or her home really exists and has sufficient room for hosting the applicant, proof that the applicant has obtained health and evacuation insurance, etc. Some countries ask for proof of health status, especially for long-term visas; some countries deny such visas to persons with certain illnesses, such as AIDS. The exact conditions depend on the country and category of visa. Notable examples of countries requiring HIV tests of long-term residents are Russia[4] and Uzbekistan.[5] However, in Uzbekistan, the HIV test requirement is sometimes not strictly enforced.[5] Other countries require a medical test which includes an HIV test even for short term tourism visa. For instance Cuban citizens and international exchange students require such a test approved by a medical authority to enter Chilean territory.
The issuing authority may also require applicants to attest that they have had no criminal convictions, or that they do not partake in certain activities (like prostitution or drug trafficking). Some countries will deny visas if the travelers passports show evidence of citizenship or travel to a country which is considered hostile by that country. For example, some Arabic oriented countries will not issue visas to nationals of Israel and those whose passports bear evidence of visiting Israel.
