That's a rather open-ended question. But here's a quick demonstration of some of XML::LibXML's capabilities...

use v5.14;
use syntax qw( junction );
use XML::LibXML 2 ':all';

my $xml = XML::LibXML->load_xml( IO => \*DATA );

my ($foo) = $xml->getElementsByTagName('foo');
say $foo;                  # says '<foo>Hello World</foo>'
say $foo->textContent;     # says 'Hello World'

my ($bar) = $xml->findnodes('//bar');  # xpath
say $bar;                  # says '<bar quux="1"/>'
say $bar->{quux};          # says '1'

my @baz = $xml->findnodes('//baz');
say $_->{xyzzy} for @baz;  # says 'a' then 'b' then 'c'

my ($comment) = 
    grep { $_->nodeType eq none(XML_ELEMENT_NODE, XML_TEXT_NODE) }
    $xml->documentElement->childNodes;
say $comment;

__DATA__
<document>
    <foo>Hello World</foo>
    <bar quux="1" />
    <baz xyzzy="a" />
    <baz xyzzy="b" />
    <baz xyzzy="c" />
    <!-- yes, this is part of the DOM -->
</document>
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Hi tobyink, thank u so much for ur help..

1.This is my xml document

<Order>
<Date>2003/07/04</Date>
<CustomerId>123</CustomerId>
<CustomerName>Acme Alpha</CustomerName>

<Item>
<ItemId> 987</ItemId>
<ItemName>Coupler</ItemName>
<Quantity>5</Quantity>
</Item>
<Item>
<ItemId>579</ItemId>
<ItemName>Clasp</ItemName>
<Quantity>1</Quantity>
</Item>
</Order>

2.my output should be
Date:2003/07/04
CustomerId:123...etc..like this

3.i have to select the element nodes without having to
specify their names..and retrieve the element
data value..in the same order as the elements in xml document

could plz help me for this..

open file.xml ;
for //text() {
    if xsh:matches(., '\S')
        echo concat(name(..), ':') (.) ;
}
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