File Download code in php

In html just create a button and link this php code to it

<?php
        $filename ="htmlquestions.rar";       -->specify the file which you want to download
        header('Content-Description: File Transfer');
        header('Content-Type: application/octet-stream');
        header('Content-Disposition: attachment; filename="'.$filename.'"');
        header('Expires: 0');
        header('Cache-Control: must-revalidate');
        header('Pragma: public');
        header('Content-Length: ' . filesize($filename));
        flush(); // Flush system output buffer
        readfile($filename);
        exit;
?>
Note:- the file you want to download must be present in same directory