Не получается прикрепить файл PHPMailer

Форма:

<form action="" class="modal_form" enctype="multipart/form-data"> 
                            <input class="modal_input modal_input--name" type="text" placeholder="Введите имя"> 
                            <input class="modal_input modal_input--phone" type="text" placeholder="Введите телефон"> 
                            <input class="modal_input modal_input--mail" type="text" placeholder="Введите e-mail"> 
                            <input type="hidden" name="MAX_FILE_SIZE" value="30000" /> 
                            <input name="userfile" type="file"> 
                            <textarea class="modal_textarea" name="" id="" cols="30" rows="10" placeholder="Текст заявки"></textarea> 
                            <button type="button" class="modal_btn">отправить заявку</button> 
                        </form>

<?php
require_once __DIR__.'/vendor/autoload.php';

use PHPMailer\PHPMailer\PHPMailer;

if(strlen($_POST['ms'])>4 and strlen($_POST['name'])>1 and strlen($_POST['phone'])>4){
error_reporting(E_ALL);
ini_set("display_errors", 1);
    function send_email($to,$theme,$message){   
        $mail = new PHPMailer(true); // Passing `true` enables exceptions
        $uploadfile = tempnam(sys_get_temp_dir(), hash('sha256', $_FILES['userfile']['name']));
        try {
            //Server settings
            $mail->SMTPDebug = 0; // Enable verbose debug output
            $mail->isSMTP(); // Set mailer to use SMTP
            $mail->CharSet = 'UTF-8';
            $mail->Host = 'smtp.mail.ru'; // Specify main and backup SMTP servers
            $mail->SMTPAuth = true; // Enable SMTP authentication
            $mail->Username = ''; // SMTP username
            $mail->Password = ''; // SMTP password
            $mail->SMTPSecure = 'tls'; // Enable TLS encryption, `ssl` also accepted
            $mail->Port = 587; // TCP port to connect to
            $mail->SMTPOptions = array(
                'ssl' => array(
                    'verify_peer' => false,
                    'verify_peer_name' => false,
                    'allow_self_signed' => true
                )
            );  
            //Recipients
            $mail->setFrom('', '');
            $mail->addAddress('', ''); // Add a recipient
            $mail->isHTML(true); // Set email format to HTML
            $mail->Subject = 'Customer order Corplex';
            $mail->Body = 'Name: '.$_POST['name'].'<br /> Phone: '.$_POST['phone'].'<br /> Message: '.$_POST['ms'].'<br /> E-mail: '.$_POST['mail'];
            $mail->addAttachment($uploadfile, $_FILES['userfile']['name']);
            $mail->AltBody = 'Application';
            $mail->send();
            echo '+';
        } catch (Exception $e) {
            echo 'Message could not be sent. Mailer Error: ', $mail->ErrorInfo;
        }

    }
    if(send_email('uzi.no.uzi.web@gmail.com','Заказ', 'Имя:'.$_POST['name'].'. <br >Cообщение: '.$_POST['ms'].'. <br> Почта: '.$_POST['mail'])){
        echo "+";
    }
}
?>

В ответе получаю такие ошибки

Notice: Undefined index: userfile in W:\domains\new.loc\wp-content\themes\uslugi\send_t.php on line 16

Notice: Undefined index: userfile in W:\domains\new.loc\wp-content\themes\uslugi\send_t.php on line 42 Message could not be sent. Mailer Error: Could not access file: uploads/

В чем проблема?