A visa is a document, stamp or other mark, usually placed in a passport, showing that the holder has permission to enter or leave and usually stay in the state or territory of issue. Visas are usually issued to foreign nationals but may be required of citizens as well under certain conditions. Depending on the status of the person applying for entry, a visa may not be required; for example, a British citizen may usually enter France as a temporary visitor without a pre-approved document.
Visas vary in the conditions of entry and stay or residence. Very often, the same visa document, stuck or stamped into a page of a passport, allows the holder to both enter and stay in the country. This may be for work, study, or temporary visiting purposes; other categories may also exist, and the holder may have to apply for a new visa in the event of a significant change in their status, such as a new job.
The visa may allow the holder to leave and re-enter once or more (double or multiple entry visas), or a single entry alone may be permitted. A visa is usually valid for a set period of time, though some are valid indefinitely (such as those allowing permanent residency). Failure to apply for renewal or leave by the expiry date is a criminal offence in many countries and can be punished by fines, imprisonment and deportation. A visa is also usually valid for a limited period of time between issuance and first entry, and expires if not used beyond that date.
Some countries separate permission to enter from that of residence or stay. For example, a visa for Japan only indicates that a foreign national has been conditionally cleared to apply for entry to the country (and re-entry, if it is not a single-entry visa). Actual residence or temporary visitor permission are held via a 'Residence Card' (for foreign nationals living in Japan) or a second temporary 'Status of Residence' passport stamp.
Typically, citizens of a country do not need a visa to reside there, but may require one to leave: North Korea is one such example. Other countries may require immigration officials to see an entry visa for the traveller's destination before allowing them to leave