To create a new WHM user with root privileges:
- create a new Reseller user
- go on WHM -> Resellers -> Reseller Center
- Select the user you want to modify
- Select Reseller Modifications -> Edit Reseller Nameservers and Privileges
- In "Feature Limits (ACL Lists)" check the box "Everything"
- Click on "Save All Settings"
NOTE: creating such a user is potentially dangerous. We suggest to protect it with a very strong password and 2FA.