With default OTRS there is no way to validate users before they are activated. This module sets the newly created users in 'invalid-temporarily' state (configurable) and creates a new Ticket in a configurable queue.
It adds a new Config group to SysConfig, and also changes the default text that is emailed when the new account is created.
You will typically use this module if you would like to manage which CustomerCompanies have which CustomerUsers.