career form sent to email php script free

<?php

// if there is post
if (isset($_POST)&& !empty($_POST)){
      
    //if there is an attachment
    if (!empty($_FILES['attachment']['name'])){
        //store some variable
        $file_name = $_FILES['attachment']['name'];
        $temp_name = $_FILES['attachment']['tmp_name'];
        $file_type = $_FILES['attachment']['type'];
              
        //get the extension of the file
        $base = basename($file_name);
        $extension = substr(&$base, strlen($base)-4,strlen($base));