how to change my email address because it's on the dark web

Thunderbird for android is a client not the email provider. You can create a new email account with gmail or any other provider such as Yahoo, icloud, gmx, mail.com etc

Hi,

This forum is intended to help users with Mozilla products, such as Thunderbird or Firefox. Your question appears to be outside the scope of our support forum, so as a moderator, I’m going to lock the thread and mark it as off-topic. Please see Mozilla Support rules and guidelines for more information.