Types of Environment variables in QTP / UFT

Below are the types of environment variables in QTP

1) Built-in - Used to extract test specific and machine/OS information. E.g ActionName, LocalHostName and OS to name a few.

2) User-defined Internal - Defined for the test and available only to the test in which it is defined.

3) User-defined External - Can be used across tests and can be loaded from an external xml file dynamically at run time or at the test level.

More Details on this topic, click on Environment Variable Loading