WHM (WebHost Manager)
WHM, short for WebHost Manager, is a web-based server administration panel from cPanel Inc. It sits above individual cPanel accounts and lets hosting providers and system administrators manage a whole server: creating and suspending hosting accounts, configuring PHP versions and modules, managing DNS zones, packages, and reseller privileges.
While cPanel is the interface end-users get to manage their own hosting account, WHM is the administrative layer used to provision and manage those cPanel accounts across the server.
PHP applications deployed on WHM/cPanel-managed servers are typically constrained by the PHP versions, extensions, and configuration values exposed through WHM’s MultiPHP Manager.