If you’re having trouble signing in or you have serious concerns about your account’s security, closing your account isn’t your only option.
Important – If you close your account, all your Yahoo account’s services will be discontinued.
Visit the this Terminating your Yahoo account page link:
If you use a phone number to sign in – visit our alternative account termination page instead.
Read the information under “Before continuing, please consider the following information.”
Confirm your password.
Forgot your password? – Recover it with the Yahoo Password Helper.
Click Terminate this Account.
How to Delete Yahoo Account Permanently 2016