Parameters and Function of every control panel are described in a separate article of our Documentation (the articles are generated automatically). They contain all of the functions and parameters, which, however, may be not available in your installation.
Use the mgrctl -i utility to get up-to-date information.
To retrieve a full list of BILLmanager functions, you may execute the command.
To retrieve data description (the lang parameter can be used to get information in a required language).
In some of the most complicated cases, you can perform operations in your browser and view requests in the log file of the control panel.