use strict;
use warnings;
use 5.012;

use XML::Simple;

my %form_data = (
    name   => 'Joe',
    weight => 180,
);

my $xml_obj = XML::Simple->new(RootName => 'form1');

say $xml_obj->XMLout(
    \%form_data, 
    noattr => 1,
    xmldecl => q{<?xml version="1.0">},
);

--output:--
<?xml version="1.0">
<form1>
  <name>Joe</name>
  <weight>180</weight>
</form1>