<?php
$file = 'monkey.gif';

if (file_exists($file)) {
    header('Content-Description: File Transfer');
    header('Content-Type: application/octet-stream');
    header('Content-Disposition: attachment; filename="'.basename($file).'"');
    header('Expires: 0');
    header('Cache-Control: must-revalidate');
    header('Pragma: public');
    header('Content-Length: ' . filesize($file));
    readfile($file);
    exit;
}
?>

header('Content-Description: File Transfer');
    header("Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
    header("Content-Disposition: attachment; filename=\"".basename($fileLocation)."\"");
    header("Content-Transfer-Encoding: binary");
    header("Expires: 0");
    header("Pragma: public");
    header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
    header('Content-Length: ' . filesize($fileLocation)); //Remove

    ob_clean();
    flush();

    readfile($fileLocation);