Your mail is yours, and you can take it with you. Doota exports a whole mailbox
as an .mbox file — the standard mail-archive format that Thunderbird,
Apple Mail, and most other mail apps can import.
Open Account → Mail and find Export mailbox, then hit Export mailbox (.mbox). Doota confirms which address you’re exporting, gathers your messages, and gives you a Download button when it’s ready. You’ll see how many messages it packed and when.