You can delete your Yahoo account in four easy steps.
First, visit https://edit.yahoo.com/config/delete_user and enter the username and password of your Yahoo account.
Second, read over the Account Termination page; if you find that you will lose access to necessary services, then you probably won’t want to delete your account. If you still wish to delete it, proceed to the next step.
Third, confirm your password and input the captcha code.
Finally, click the button labeled “Terminate this Account” to delete your Yahoo Account.