How to create a mail server to send messages?

Question

Mail server

Hello.
You need to set up a server to send e-mails to the user's mail to confirm registration. It is important that the mail client sends but does not receive mail.
Please tell me more like software and materials.

Answer 1

For example, like this https://www.digitalocean.com/community/tutorials/h...
There is nothing more to answer, because no details are provided.