There is no such thing as a "Thunderbird account" or "Thunderbird password". Neither Thunderbird nor Mozilla are an email provider. You've set up an account with an email provider, e.g. Gmail or Yahoo. Then you use Thunderbird as an email client to access mail for that account on your email provider's server, or to send mail via your email provider's server. If you lost your account password check with your email provider for password recovery options.

Where to find the password recovery options ?

You'll have to talk to your email provider. If they do have a support web site, that may be a good start.