You can follow below steps to whitelist domain for emails in cpanel:
- First login to cpanel.
- Click on “Spam Filters” under “Emails” section.
- Here you will find “Show Additional Configurations” option in the last. You will find this option if your hosting provider have enabled it on server.
- Now click on click "Edit Spam Whitelist settings" option.
- You will find Add A New "whitelist_from" Item option, you have to add your domain here.
- Click "Add A New "whitelist_from" Item".