How to get mail relay to work

[paul.greene.va]

Hello All,

Apologies in advance - I'm brand new to postfix; hopefully this question 
won't be too newbish.

I've been given a task to get a freshly installed postfix server to 
forward mail from an application - i.e. when changes are made to an 
application, the application is supposed to send an email notification 
to a specified email address.

There is an existing functioning postfix server that this new one is 
replacing - the old one is running on redhat 6, postfix version 2.6; the 
new one is running on redhat 7, postfix version 2.10.

I grepped for all of the uncommented lines in /etc/postfix/main.cf on 
both the old and the new server and compared them; the configuration was 
the same on both. The "relayhost = " parameter and the "mynetworks =" 
parameter was the same on both

This mail server isn't being used as a general mail server where users 
are communicating with each other. It's only used for applications to 
send out notifications.

Besides /etc/postfix/main.cf, is there any other config files that need 
to be edited to enable this mail relaying?

Paul