At the moment, UK is currently an European Union Member State. So if you are from European Union countries, you will be able to enter UK without the need for a visa and you’re entitled to live there provided you are gainfully employed, self-employed or registered as a job seeker.
Citizens from British Oversea Territories and Common wealth who were born before January 1, 1983 can also enter United Kingdom without visa. UK also allows citizens of some countries to enter and live in UK for a maximum of 6 months. Such countries include but not limited to the following;
Andorra, Japan, Malaysia, Trinidad and Tobago, Mauritius, Mexico, United States, Taiwan, Tonga, Uruguay, Vanuatu, Vatican City, Namibia, Honduras, Chile, Hongkong, Brazil, Bostwana, Guinea, Canada, Brunei, Paraguay etc..
If you belong to a country outside of all these, then it is pertinent that you get a visa before you can be allowed to enter UK. All you need to do, is to apply for a visa at the British consulate or embassy in your country. In a situation where you would like to work in the state, then you would also require a work permit which needs to be applied for you by your employer in the United Kingdom.
UK visa are of various types which can easily be divided into five basic categories which are; work visas, tourist and short stay visas, student visas, trasit visas, and family visas.
The requirements for getting each type of visas varies and also requires a point based assessment which you are required to pass befoe you can be issued a visa.