You can have email everywhere with IMAP and SMTP. Even phones. One thing that is difficult running your own mail server is assuring you do not get spam filtered for running on a cloud server netblock. I had to set up DKIM, DMARC and SPF.

I used this for setup: https://help.ubuntu.com/community/Postfix

To get a full stack going with proper SSL auth it is somewhat involved. The good thing is once you do it, it works reliably and you OWN your email. Complying with every anti spam measure is critical though because you will be most likely sending mail to others on large servers that will reject your mail otherwise. Even then I had a lot of problems with Yahoo to get whitelisted, and Verizon just summarily blocks Digital Ocean hosts.

Ars Technica had decent little guides for setting up secure web server and mail server;

Secure Web Server series;

https://arstechnica.com/series/web-served/

Mail Server Series

https://arstechnica.com/information-technology/2014/02/how-t...

https://arstechnica.com/information-technology/2014/03/takin...

https://arstechnica.com/business/2014/03/taking-e-mail-back-...

https://arstechnica.com/information-technology/2014/04/takin...

This is a famous guide most self-hosting users run:

https://workaround.org/ispmail/jessie

I use cloudron for self-hosting mail. Yes, it works perfectly fine on mobile.