So, what I'm going to show you is how to access your domain emails from gmail, and send emails using your gmail as your domain emails.
I'm sure a lot of you already know this trick.
First, what you are going to do is login to your cpanel, go to the "Forwarders" under the Mail section in the cpanel, and forward emails from your domain email to your personal gmail.
What you want to do now is, login to your gmail, go to "Settings" on the top-right corner (the wheel icon), go to "Accounts and Import", and "Add another email address you own" under the "Send mail as:" section.
After you've added your domain email, and verified, that allows you to send emails from your domain email using gmail.
So now, you will receive all emails to your gmail, and you can reply them using gmail, but acting as your domain email.
Hope that helped!