Setting up Domain email is pretty straight forward and is included in most cPanel hosting plans. However, you can soon start to encounter problems with email deliverability and bounced emails or, worse, your emails getting trapped as spam.
There are no magic bullets here and the key is to make sure you are sending relevant emails to your customers and not spamming them with irrelevant rubbish.
Her are few tools I use to test domain email deliverability and find issues.
SPF and DKIM DNS records
If you are sending emails from your domain email, as a bar minimum you must have SPF and DKIM authentication records set up on your domain.
These are DNS records that email servers receiving emails from your domain use to test that the email is really from your server and not some spam server spoofing your server id.
Most cPanel hosting sets these up by default and there is usually a cPanel tool called ‘Email Deliverability‘. This check for the presence of SPF and DKIM records.
You can test your SPF records here: https://www.spf-record.com/spf-lookup
Email deliverability Test
you can use the mail-tester.com tool to get a deliverability report that checks SPF, DKIM and DMARC record validity and also checks many other deliverability properties including trapping via SpamAssassin.
Access the service here: https://www.mail-tester.com/