Voter registration (or enrollment) is the requirement that a person otherwise eligible to vote register (or enroll) on an electoral roll before they will be entitled or permitted to vote. Such enrollment may be automatic or may require application being made by the eligible voter. The rules governing registration vary between jurisdictions. Some jurisdictions have "election day registration" and others do not require registration, or may require production of evidence of entitlement to vote at time of voting. In some jurisdictions registration by those of voting age is compulsory, while in most it is optional. In jurisdictions where registration is voluntary, an effort may be made to encourage persons otherwise eligible to vote to register, in what is called as a voter registration drive.
Registered persons may need to re-register or update their registration if they change residence or other relevant information. In some jurisdictions, when a person registers a change of residence with a government agency, say, for a driver's license, the government agency may forward the information to the electoral agency to automatically update the voter registration information.
Even in countries where registration is the individual's responsibility, many reformers, seeking to maximize voter turnout, argue for a wider availability of the required forms, or more ease of process by having more places where they can register. The United States, for example, the National Voter Registration Act of 1993 ("Motor Voter Law") and similar laws require states to offer voter registration at motor vehicle departments (driver's license offices) as well as disability centers, public schools, and public libraries, in order to offer more access to the system. State authorities are also required to accept mail-in voter registrations. Many jurisdictions also offer online registrations. Wikipedia