Have you already purchased your server and wanting to upgrade to a dedicated IP?
You can learn more about what a dedicated IP is here:
First, login to https://billing.plox.host/
and visit the service you wish to upgrade.
Click the "Upgrade/Downgrade Options"
From here, click "Dedicated IP" and set it to "Yes"
On the next screen, you will pay the extra charge. After, your server will be applied with a dedicated IP.