How to remove your Twitter account
Use the link below to deactivate your account. Twitter calls it ‘deactivation’ instead of ‘removal’. In spite of this, it seems your info will actually be removed. Read https://support.twitter.com/entries/15358-how-to-deactivate-your-account for more info.
Direct removal link: https://twitter.com/settings/accounts/confirm_deactivation
Helpful Trick: Removing online data
Publicly visible text/images often aren’t properly removed even when you succeed in removing an account. Try editing or removing them manually before removing the account itself. If you’re unsure what happens to your tracks: this can be found mostly in the Terms of Service/Privacy Policy; otherwise you can always contact Twitter and ask personally. By the way, removal requests don’t necessarily mean your data will actually be removed (e.g. due to legal obligations).
Helpful Trick: Remove third-party logins
If you signed up for Twitter using a third-party login such as Facebook or Twitter, you probably want to revoke all access from Twitter. Click here to find out how.