The Types File

PowerShell's type extensions are defined in an XML file that is located in the PowerShell installation folder called Types.ps1xml. You can edit this file in any text editor such as Notepad. Alternatively, the file can be edited in an XML editor such as SAPIEN PrimalScript. Not every type supported by PowerShell is listed. Instead, only the types being extended need to be included in this file. Other types simply exist with their default capabilities.

You can also create your own type flies, giving them a .ps1xml filename extension. They'll use the same format as PowerShell's default file, and you load them into PowerShell using the Update-TypeData cmdlet. Using your own type files allows you to extend the type system without modifying the default file provided by Microsoft.