如何使用ajax请求发送带有附件的电子邮件

我正在制作一个表格来发送带有两个附件的电子邮件。仅当我不使用ajax请求时发送电子邮件才有效。那些。当脚本未连接main.js并提交表单 ( submit) 时，则成功发送带有附件的信件。但是当我提交与连接相同的表单时main.js，ajax请求成功但附件未发送

main.js

document.addEventListener("DOMContentLoaded", function() {
  alert("ready");
  $('#visa-form').submit(function(e) {
    var $form = $(this);
    $.ajax({
      type: $form.attr('method'),
      url: "mail.php",
      data: $form.serialize()
    }).done(function() {
        alert("Заявка на визу отправлена успешно");
    }).fail(function() {
         alert("Произошла ошибка при отправке заявки");
    });
    e.preventDefault(); 
  });
});

邮件.php

<?php 
use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\Exception;
require 'PHPMailer/src/Exception.php';
require 'PHPMailer/src/PHPMailer.php';
require 'PHPMailer/src/SMTP.php';
$message = '';

function clean_text($string)
{
    $string = trim($string);
    $string = stripslashes($string);
    $string = htmlspecialchars($string);
    return $string;
}
$mail = new PHPMailer;
$mail->CharSet = "utf-8";

try 
{
    if(isset($_POST["user_fullname"]))
    {       
        $user_photo = 'uploads/' . $_FILES["photo_scan"]["name"];
        $user_passport_scan = 'uploads/' . $_FILES["passport_scan"]["name"];
        move_uploaded_file($_FILES["photo_scan"]["tmp_name"], $user_photo);
        move_uploaded_file($_FILES["passport_scan"]["tmp_name"], $user_passport_scan);

        $message = '
            <meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
            <h3 align="center">Заявка с сайта tulpantravel.ru</h3>
            <table border="1" width="100%" cellpadding="5" cellspacing="5">
                <tr>
                    <td width="30%">ФИО</td>
                    <td width="70%">' . $_POST["user_fullname"] . '</td>
                </tr>
                <tr>
                    <td width="30%">Пол</td>
                    <td width="70%">' . $_POST['user_gender'] . '</td>
                </tr>
                <tr>
                    <td width="30%">Номер телефона</td>
                    <td width="70%">' . $_POST["user_phone"] . '</td>
                </tr>
                <tr>
                    <td width="30%">Электронная почта</td>
                    <td width="70%">' . $_POST["user_email"] . '</td>
                </tr>
                <tr>
                    <td width="30%">Место работы</td>
                    <td width="70%">' . $_POST["user_workplace"] . '</td>
                </tr>
            </table>
        ';
        $mail->IsSMTP();
        $mail->Host = 'smtp.mail.ru';
        $mail->Port = '465';
        $mail->SMTPAuth = true;
        $mail->Username = '*********';
        $mail->Password = '*********';
        $mail->SMTPSecure = 'ssl';
        $mail->From = '*********';
        $mail->FromName = '*********';
        $mail->AddAddress('***********', '********');
        $mail->IsHTML(true);
        $mail->AddAttachment($user_photo);
        $mail->AddAttachment($user_passport_scan);
        $mail->Subject = 'Заявка с сайта **********';
        $mail->Body = $message;
        if($mail->Send())
        {
            // ready
        }
        else
        {
            // failure
        }
    }
} 
catch (Exception $error)
{
    echo 'Произошла ошибка при отправке запроса: ' . $mail->ErrorInfo;
}
finally
{
    // finally
}

索引.php

<div id="su-re-modal" class="form">
    <div class="modal-title" style="margin-bottom: 20px;">
        <div class="modal-title">Заявка на визу</div>
        <div class="modal-close su-re-modal_close"></div>
    </div>
    <form id="visa-form" method="post" action="mail.php" enctype="multipart/form-data">
        <div class="form-group">
            <label>ФИО</label>
            <input type="text" name="user_fullname" class="form-control" required/>
        </div>
        <div class="form-group">
            <label>Пол</label>
            <select name="user_gender" class="form-control">
                <option value="Мужской">Мужской</option>
                <option value="Женский">Женский</option>
            </select>
        </div>
        <div class="form-group">
            <label>Номер телефона</label>
            <input type="text" name="user_phone" class="form-control" pattern="\d*" required/>
        </div>
        <div class="form-group">
            <label>Эл. почта</label>
            <input type="email" name="user_email" class="form-control" required/>
        </div>
        <div class="form-group">
            <label>Место работы</label>
            <input type="text" name="user_workplace" class="form-control" required/>
        </div>
        <div class="form-group">
            <label>Загрузить фото</label>
            <input type="file" name="photo_scan" required/>
        </div>
        <div class="form-group">
            <label>Загрузить скан паспорта</label>
            <input type="file" name="passport_scan" required/>
        </div>
        <div class="form-group" align="center">
            <input type="submit" name="submit" value="Отправить заявку" class="btn btn-info" />
        </div>
    </form>
</div>
<script src="jquery-3.5.1.min.js"></script>
<script src="main.js"></script>

PS所有三个文件都在同一个目录中