Пример кода<input type="file" multiple name="DOCUMENTS[]">

<?
$countFiles = count($_FILES["DOCUMENTS"]['name']);
$files = [];
for ($i = 0; $i < $countFiles; $i++) { 
    $files[$i]['name'] = $_FILES["DOCUMENTS"]['name'][$i];
    $files[$i]['type'] = $_FILES["DOCUMENTS"]['type'][$i];
    $files[$i]['tmp_name'] = $_FILES["DOCUMENTS"]['tmp_name'][$i];
    $files[$i]['error'] = $_FILES["DOCUMENTS"]['error'][$i];
    $files[$i]['size'] = $_FILES["DOCUMENTS"]['size'][$i];
}

"PROPERTY_VALUES" => [
    'DOCUMENTS' => $files
]
?>