You could create a message filter to do it. Tools menu or ≡ button, then tools > Message filters https://support.mozilla.org/en-US/kb/organize-your-messages-using-filters But it's better to set forwarding rules at the server so Thunderbird doesn't have to run all the time to do it (and forwarding won't happen, if you forget to leave Thunderbird running, until you run Thunderbird again).

thanks!