Its very easy to Add any DNS records from CWP DNS Zone .
You can add MX records , txt records ( for any domain verification like Google verification , etc . ) for MX records you and exchange emails between with any outside email provider , like G suite , Zoho mail , etc .
You need to login CWP and from left side bar . you can find DNS Functions -> DNS Zone Editor
As like below screenshot
Then just select domain name from drop-down and click on add Type record or you can edit from the list below