Can you create an xml in an .xml file and help php?

Good community, I have a doubt, I have created an xml view from a file with extension .php, but I would like to know if, Can I replicate what I have done but from an .xml file ?. Thank you very much in advance.

    <?php
$html = "";
$url = "https://sports.yahoo.com/soccer/mls/rss.xml?shangrila=1";
$xml = simplexml_load_file($url);

header("content-type: text/xml");
echo('<?xml version="1.0" encoding="UTF-8" ?>');
// $html .= '  <rss version="2.0">'; // si descomentas se verá como un rss
$html .= '    <channel>';
foreach ($xml->channel as $object) {
  $html .='       <title> '.$object->title.' </title>'; // cabecera
  $html .='       <description> '.$object->description.' </description>';

}

  for($i=0; $i<10;$i++){ // cantidad de noticias
  $title = $object->item[$i]->title;
  $link =  $object->item[$i]->link;
  $description = $object->item[$i]->description;
  $pubDate = $object->item[$i]->pubDate;
  $guid = $object->item[$i]->guid;

  $html .='<item>';
  $html .='       <title> '.$title.' </title>';
  $html .='       <link> '.$link.' </link>';
  $html .='       <description>'.$description.' </description>';
  $html .='       <pubDate> '.$pubDate.' </pubDate>';
  $html .='       <guid> '.$guid.' </guid>';
  $html.='</item>';
}
    $html .= " </channel>";
  // $html .= "      </rss>";
//
  echo $html;
  file_put_contents("rss.xml",$html);
 ?>

PS: if you want to see the code that I created, let me know and I'll post it.