I just want to set up email address accounts for a few domains on my server.

Postfix is working and sending out a newsletter. DNS is handled by my server host admin system.

I did this in the postfix main.cf

myhostname = mail.example.com
mydomain = example.com
myorigin = $mydomain
inet_interfaces = all
mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
mynetworks = ip-address/36
relay_domains =
home_mailbox = Maildir/

Then made an account:-
[root~]adduser -s /sbin/nologin info;
[root~]passwd info

restarted postfix

But can not get info@example.com to send or receive emails.

I am likely doing something very basic wrong.

Actually, I am not sure if the above method is really what I am looking for anyway. I have multiple domains and want email accounts for each.

So how are you trying, and what does /var/log/mail.log (or equivalent) say?As long as the usernames are unique, just list the domains in the mydestination directive.
If you want the same usernames at different domains you should look at the documentation for a virtual domains setup.
Although if it just a couple, this can generally be handled much easier with full-address aliases to unique local usernames.
i.e. map info@domain1.com to info1
info@domain2.com to info2 etc...