Registration as a British Citizen involves applying for citizenship by individuals who aren't born British or automatically eligible. This process typically requires meeting specific criteria, such as residence duration, good character, and adherence to immigration laws. Applicants may include those born to non-British parents in the UK or individuals with certain connections to British overseas territories. Successful registration grants full British citizenship rights, including the ability to obtain a British passport. The process is overseen by the Home Office and involves completing the relevant application forms and providing supporting documentation.