Apple's Mail.app is obtuse sometimes, but at least it has nice e-mail alias
support, as offered by e.g. Fastmail (see here).
Settings => Accounts => the account you want.
Account Information => Email Address.
Edit e-mail addresses. Add the aliases you need.
The added aliases will show up as available senders when composing.
Also within Settings => Accounts the Server settings appear to allow
switching of SMTP servers. Neat!
Apple's Mail.app is obtuse sometimes, but at least it has nice e-mail alias
support, as offered by e.g. [Fastmail][] (see [here][email-alias]).
[email-alias]: https://www.fastmail.com/help/receive/aliases.html
[Fastmail]: https://www.fastmail.com/?STKI=19315912
1. Settings => Accounts => the account you want.
2. Account Information => Email Address.
3. Edit e-mail addresses. Add the aliases you need.
The added aliases will show up as available senders when composing.
Also within Settings => Accounts the Server settings appear to allow
switching of SMTP servers. Neat!