How does domain mail work?

Question

Mail for domain

I don’t understand a little how email works, so I really want to fill this gap. Yandex and Google provide mail for your domains, so this can be repeated. Let's take a situation where I have a 123.com domain and a VPS. I want to make sure that when sending from a third-party service to [email protected], a message arrives somewhere and is saved. If this is not possible, then how can I use cloudflare (and for example, mail for a domain from Yandex) at the same time?

Answer 1

we take a VPS
, put iredmail there,
and read, read, read...