You must be registered to vote to take part in any election. Visit www.gov.uk/register-to-vote to register - all you need is your National Insurance number
You are allowed to vote if you are:
Aged 18 years or over on the day of poll and are either:
A British or Irish citizen living in the UK, or
A Commonwealth citizen living in the UK who has leave to remain in the UK or who does not require leave to remain in the UK, or
A British citizen living overseas who has been registered to vote in the UK in the last 15 years
You don't need to register to vote if you are already on the electoral roll.