There’s a paid Thunderbird add-on named Owl which adds Exchange support (10$/year). It’s not perfect but does the job.

@Tangent5280 for context: Exchange is a custom email/collaboration suite protocoll by Microsoft. Thunderbird doesn’t support that. Often, it’s not really a problem, because one can enable SMTP/IMAP/POP access for their O365 accounts. However an administrator has to do that, and, for instance, my university doesn’t allow that.