We can change the root password of server from WHM using below steps as given below:
Step 1. Login to WHM. (http://yourserverip:2085) or (https://yourserverip:2088)
Step 2. After Logged in you will see the “server configuration” tab in left sidebar, Click on change root password under server configuration.
Step 3. Enter new password or you can click on Generate password button to generate it by system.
Step 4. Confirm new password.
Step 5. Click on Change password button.