electronic mail

Transfer mail with an MTA like postfix (SMTPS)
Access mail with a MDA like dovecot (IMAP)

See the arch wiki at https://wiki.archlinux.org/title/Mail_server

See https://github.com/LukeSmithxyz/emailwiz for an all-in-one solution (adapt to your own needs)

Landchad also useful https://landchad.net/mail/

Check correct configuration:
https://internet.nl/mail/
https://www.checktls.com/
https://www.hardenize.com/
https://developer.mozilla.org/en-US/observatory/
https://multirbl.valli.org/lookup/ check if IP blacklisted

Bring your own domain, they run the servers

https://purelymail.com/ affordable (flexible) pricing

Use a smarthost if you can't send mail yourself (blocked port, bad reputation)
If sending plaintext emails, you trust the smarthost provider to not read/analyse/sell your data.

See the FSF's infographic on using PGP for E2E encryption at https://emailselfdefense.fsf.org/en/

Based on Luke Smith's emailwiz script at https://github.com/LukeSmithxyz/emailwiz
Also see the arch wiki at https://wiki.archlinux.org/title/Mail_server
Originally planned to use the ISPMail Guide at https://workaround.org/ but it setup things in a bloated way (unnecessary databases and other)