You do not log into Thunderbird. You log into your email account with your email provider. There is no Thunderbird username. Again, this is something that is part of your email address and account. You need none of the info you list to remove an account from Thunderbird. Right click the account on the left side in the Folder Pane and select settings. Select the account to remove and click Account Actions. Remove Account is under Account Actions. To add an account to Thunderbird you obviously will need to know the username and password for that account. Contact your email provider if you do not know this info.

Thanks really helpful & easy once you know what to do. thanks again