How to send an email with SMTP in php?

I'm trying to send an email with SMTP in php for my contact us section but whatever i do it just doesn't work. I did exactly what i read in https://github.com/PHPMailer/PHPMailer . please tell me where i'm going wrong? here is my code:

include_once 'model/Mcont.php';

require 'public/include/PHPMailer.php';

$mail = new PHPMailer();

    

if(isset($_POST['btn-contact'])){
  if(empty($_POST['text']) || empty($_POST['email']) || empty($_POST['text'])){
     header("location:http://website.com/?c=cont&warning=e");
 }else{

    $email = $_POST['email'];
    $userName = $_POST['username'];
    $text = $_POST['text'];

                     //Server settings
    $mail->SMTPDebug = SMTP::DEBUG_SERVER;                      //Enable verbose debug output
    $mail->isSMTP();                                            //Send using SMTP
    $mail->Host = 'mail.example.com';              //Set the SMTP server to send through
    $mail->SMTPAuth = true;                                   //Enable SMTP authentication
    $mail->Username = 'username';                 //SMTP username
    $mail->Password = 'password';                               //SMTP password
    $mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;            //Enable implicit TLS encryption
    $mail->Port = 587;                                    //TCP port to connect to; use 587 if you have set `SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS`
        //Recipients
    $mail->setFrom($email, $userName);
    $mail->addAddress('info@example.com', 'me');     //Add a recipient
    $mail->addReplyTo($email, 'reply');
    $mail->addCC('info@example.com');
    $mail->addBCC('info@example.com');

    //Content
    $mail->isHTML(true);                                  //Set email format to HTML
    $mail->Subject = 'ARTALEF WEBSITE';
    $mail->Body    = $text.'<br>';
    $mail->AltBody = 'This is the body in plain text for non-HTML mail clients';

    $mail->send();
    header("location:http://website.com/?c=cont&s=em_s");

    }
 }

  include_once 'view/cont/cont.php';

 ?>

source https://stackoverflow.com/questions/68145366/how-to-send-an-email-with-smtp-in-php