The XDocument class is used to load or parse a document. XML content may be cast to an XDocument in the same way that content is cast using the [Xml] type accelerator:

using assembly System.Xml.Linq 
[System.Xml.Linq.XDocument]$xDocument = @" 
<?xml version="1.0"?> 
<cars> 
<car type="Saloon"> 
<colour>Green</colour> 
<doors>4</doors> 
<transmission>Automatic</transmission> 
<engine> 
<size>2.0</size> 
<cylinders>4</cylinders> 
</engine> 
</car> 
</cars> 
"@ 
$xDocument.Save("$pwdcars.xml") 

If the content has been saved to a file, the Load method may be used with a file name:

$xDocument = [System.Xml.Linq.XDocument]::Load("$pwdcars.xml")