Single line comments

In PowerShell single line comments start with a hash symbol, everything to the right of the # will be ignored

# This is a comment in PowerShell
Get-ChildItem

Multi line comments

You can also have multi-line comments using <# and #> at the beginning and end of the comment respectively.

<#
This is a   
multi-line   
comment   
#> 
Get-ChildItem      

Comment based help

Comment-based help topics can be added to functions and scripts. This is done using special help comment keywords that start with a period. Examples of these are below, you can add as many or as few of these to your script as needed to provide the relevant level of detailed help.

<#
.SYNOPSIS
    This script/function does - What?

.DESCRIPTION
    A more detailed description of why and how the function works.

.PARAMETER DemoParam1
    The parameter DemoParam1 is used to define the value of blah and also blah.

.PARAMETER DemoParam2
    The parameter DemoParam2 is used to define the value of blah and also blah.

.EXAMPLE
    The example below does blah
    PS C:\> Example

.EXAMPLE
    Another example

.NOTES
    Author: Name
    Last Edit: yyyy-mm-dd
    Version 1.0 - initial release of blah
    Version 1.1 - update for blah

#>