Пример кода<?
require ($_SERVER['DOCUMENT_ROOT'] . '/bitrix/modules/main/include/prolog_before.php');

$url = $_SERVER['DOCUMENT_ROOT'] . '/upload/export.xml';

$in_xml = simplexml_load_file($url);
$data = $in_xml->ПакетПредложений->Предложения;
$parse = json_decode(json_encode($data), TRUE);

$arOffers = [];
foreach ($parse as $offer) {
    $arOffers[] = $offer;
}
?>