Do you want to use a new email address for the Mozilla Account, or do you want to have two different accounts, each with their own email address? You can change the email address via the Mozilla Account Settings page. You can add a secondary email address and confirm this email address. Once this email address has been confirmed, you can make the secondary email address your primary email address. *https://support.mozilla.org/en-US/kb/change-primary-email-address-firefox-accounts *https://support.mozilla.org/en-US/kb/add-secondary-email-address-firefox-accounts