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.