<form type="submit" enctype="multipart/form-data">
    <input type="file" name="attachment">
    <button name="submit" type="submit">SEND</button>
</form>

if(isset($_POST['submit'])){
extract($_POST);

$to="example@email.com";
$msg="email body";

require 'include/PHPMailer_master/src/PHPMailer.php';
require 'include/PHPMailer_master/src/SMTP.php';
require 'include/PHPMailer_master/src/Exception.php';
$mail = new PHPMailerPHPMailerPHPMailer(true);

enables exceptions
try {
    //Server settings
    $mail->SMTPDebug = 2;
    $mail->isSMTP();
    $mail->Host = 'smtp.siteprotect.com';
    $mail->SMTPAuth = true;
    $mail->Username = 'example@email.com';
    $mail->Password = 'password';
    $mail->SMTPSecure = 'tls';
    $mail->Port = 587;

    $mail->setFrom('example@email.com');
    $mail->addAddress($to);

    $mail->addAttachment($_FILES['attachment']['tmp_name'],
$_FILES['attachment']['name'] );

    $mail->isHTML(true);
    $mail->Subject = 'RESUME - Sales Engineer (from website careers page)';
    $mail->Body    = $msg;
    $mail->AltBody = 'This is the body in plain text for non-HTML mail clients';
    $mail->send();
    echo '<script>alert("Message has been sent");</script>';
} catch (Exception $e) {
    echo '<script>alert("Message not sent");</script>';
    echo 'Message could not be sent. Mailer Error: ', $mail->ErrorInfo;
}
}