Problem to have two email address
Start from File/New/Existing Mail Account; press Alt if the Menu Bar with File is hidden. Or, Tools/Account Settings, Account Actions, Add Mail Account...
I followed the instructions, but I can't find the boxes you mention. Another way exists?, they are emails from different domains
Thank you
Todas as respostas (1)
Please do not start a separate topic from the one you started:
https://support.mozilla.org/en-US/questions/1325049
Click the 3-bar menu icon, New, Existing Mail Account... (see picture). Or, click Account Settings at the upper right corner of the window in your picture.