The Import-Module command

PowerShell 3 and more will attempt to automatically load modules if a command from that module is used and the module is under one of the paths in the %PSMODULEPATH% environment variable.

For example, if PowerShell is started and the PSDesiredStateConfiguration module is not imported, running the Get-DscResource command will cause the module to be imported. This is shown in the following example:

PS> Get-Module PSDesiredStateConfiguration

PS> Get-DscResource

PS> Get-Module PSDesiredStateConfiguration

ModuleType Version Name                        ExportedCommands
---------- ------- ----                        ---------------- 
Manifest   1.1     PSDesiredStateConfiguration ...

In the previous example, the first time Get-Module is executed, the PSDesiredStateConfiguration module has not yet been loaded. After running Get-DscResource, a command from the PSDesiredStateConfiguration module, the module is loaded and the command is immediately executed. Once...