@gofaniyi SOGo is a "frontend" to email. The emails itself are stored in the backend which is part of Cloudron. Practically, what this means is that if you install some other email frontend like rainloop or roundcube, you will be able to see the same emails.
To answer your question, all the data will be in /home/yellowtent/boxdata/mail/vmail. You will find directories organized by domain.com/username. They are all in maildir format.
