The page is available only when the WordPress Support plugin is enabled. The plugins are bundled with IntelliJ IDEA and activated by default. If the plugins are not activated, enable them on the Plugins page of the Settings / Preferences Dialog as described in Enabling and Disabling Plugins.
Use this page to enable the use of the WordPress Content Management System through the IntelliJ IDEA user interface. To use WordPress in the command line mode, configure it as a command line tool in Command Line Tool Support: WP-CLI.