To delete your Facebook account, you first need to be able to login to the account. If you are not able to login to your account because you have forgotten the password, you can recover the password by using "Forgot your password?" option on the Facebook login page. Once you click on this option, follow on-screen instructions to reset your password.
Once you have reset the password, you can deactivate your account temporarily or delete it permanently by following the instructions mentioned in the following link:
If you are not able to login because Facebook has disabled your account, you can refer to the following link to know more about this:
Hope this will resolve your issue.