Changing your root password on a Plesk server
If you have installed cPanel/WHM to your PureSSD VPS server, then you can change the root password from within the Plesk interface.
When you have logged in to the Plesk management interface, select “Users” on the left-hand side of the page:
Choose the name of the user that you wish to update the password for. In this case, we’ve selected Administrator.
Next, select “Change Settings“. This will take you to a page with a number of options for the user. Here you will see an option to change the password.
You can also change your password from the homepage of Plesk.
In the top right corner of the page, just select your user and a drop down menu should appear. Select “Edit Profile” and the following page will have an option to change the password.