The Vultr VPS for WHMCS module at modulesgarden.com allows fully automated management of Vultr cloud servers. According to their official documentation:
The module will allow your clients to remotely control the status of a server, access the console, rebuild the VPS and many others. You will be also allowed to adjust your offer to even the most demanding needs of your clients with the wide range of configurable options.
For technical support with the Vultr VPS for WHMCS module, please see the documentation at Modules Garden.