Email is very complicated, if you want most of your mail to hit the recipients inbox. I'd highly suggest just letting gmail or some other professional email service handle your email. You can make abc.com with gmail and it's like it actually came from your domain.
https://gsuite.google.com/products/gmail/
Things you'd have to consider when hosting your own email service
- DNS
- PTR records
- RDNS records
- DKIM records
- Domain/IP Reputation
- Blacklists
- Email Server setup/maintenance
- Individual policies of the email servers you're sending mail to. For instance, if comcast.com has some policy that marks your email as spam and you have 200 people you're sending to with a comcast email address, you'd have to figure out how to get around it and fix it for just that one domain that you're sending to, and your fix might break some other email services spam filters. Now multiply that by the thousands of potential domains you'd be sending email to.
If you don't know what all of that is, or how to set it all up competently, you'd be a lot better off going with gmail or similar. They do email right and it's cheap. Otherwise, your recipient might get your email in their spam box instead of their inbox, or NOT AT ALL, which makes it difficult to be "professional" if you tell them "I never got your email" or they tell you they aren't receiving your email. You might never even know they didn't. Email needs to be very reliable.