If you have not registered to vote, or if you are registered but your details have changed, you can do so on the government voting website. You will need to have your National Insurance Number to register.
You can register to vote in any of three ways: in person, by post, or by proxy (having someone else cast the vote on your behalf).
Having a postal or proxy vote makes it easier for you to be able to vote if you are overseas. If you have a proxy vote but wish to vote in person, you should let your proxy voter know not to cast your vote, and you should ask at your local registration office where you should go to vote.