First let’s talk about what a visa is. A visa is a “conditional authorization granted by a territory to a foreigner, allowing them to enter, remain within, or to leave that territory.” Visas typically may include limits on the duration of the foreigner’s stay, areas within the country they may enter, the dates they may enter, the number of permitted visits or an individual’s right to work in the country in question. Visas are associated with the request for permission to enter a territory and thus are, in most countries, distinct from actual formal permission for an alien to enter and remain in the country. In each instance, a visa is subject to entry by an immigration official at the time of actual entry, and can be revoked at any time. Visa evidence most commonly takes the form of a sticker endorsed in the applicant’s passport or other travel document but may also exist electronically. Some countries no longer issue physical visa evidence, instead recording details only in immigration dibates.
Historically, immigration officials were empowered to permit or reject entry of visitors on arrival at the frontiers. If permitted entry, the official would issue a visa, when required, which would be a stamp in a passport. Today, travellers wishing to enter another country must often apply in advance for what is also called a visa, sometimes in person at a consular office, by post, or over the internet. The modern visa may be a sticker or a stamp in the passport, an electronic record of the authorization, or a separate document which the applicant can print before leaving home and produce on entry to the visited territory. Some countries do not require visitors to apply for a visa in advance for short visits.
Visa applications in advance of arrival give countries a chance to consider the applicant’s circumstances, such as financial security, reason for travel, and details of previous visits to the country. Visitors may also be required to undergo and pass security or health checks upon arrival at the port of entry. Some visas can be granted on arrival or by prior application at the country’s embassy or consulate, or through a private visa service specialist who is specialized in the issuance of international travel documents. These agencies are authorized by the foreign authority, embassy, or consulate to represent international travellers 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. Alternatively, in such cases visas may be pre-arranged for collection on arrival at the border. 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.