I know that we need an account to file a bug report at Bugzilla. Can I delete my account if I register and have the account.
Why would you want to? You can easily set your account to never email you. I've had a look and I don't see a "delete account" option, so I guess if you really don't want to keep the account you should use a disposable email address (ie. make a new account with one of the many sites that provides free email and don't use it for anything else).