testing.php

<?php
use Drupal\Component\Serialization\Json;

/** @var \GuzzleHttp\Client $client */
$client = \Drupal::service('http_client_factory')->fromOptions([
  'base_uri' => 'https://pweb.permata.xituz.com/',
]);

$response = $client->get('sites/default/files/feeds/dummy_mf.json');
$json_data = Json::decode($response->getBody());

$json_data = $json_data['MFProductInqRs']['MFProductInqList'];

foreach ($json_data as $data) {
  print_r($data);
}