Whether you are itching to get rid of your Yahoo Mail account due to news that the service was hacked or due to other reasons, then follow these steps. First, click here to access the account cancellation page.
If you have not yet opened your email, on the page that appears log in with the e-mail address and password of the mail you want to delete, if you have already done so, you will be taken directly to this page:
Enter your password in the field provided for it, then enter the code that appears and click Terminate this account. Done! You will see a window confirming the deactivation of your account: