Nodes can be added by using the Add methods, which include Add, AddAfterSelf, AddBeforeSelf, and AddFirst, for example:

[XDocument]$xDocument = @" 
<?xml version="1.0"?> 
<list type='numbers'> 
    <name>1</name> 
</list> 
"@ 
$xDocument.Element('list'). 
    Element('name'). 
    AddAfterSelf(@( 
        [XElement]::new('name', 2), 
        [XElement]::new('name', 3), 
        [XElement]::new('name', 4) 
    )) 

The different Add methods afford a great deal of flexibility over the content of a document; in this case, the new elements appear after the <name>1</name> element.