Formulaire de contact et Recaptcha invisible

<?php
$name = $_POST['name'];
$email = $_POST['email'];
$phone = $_POST['phone'];
$call = $_POST['call'];
$website = $_POST['website'];
$priority = $_POST['priority'];
$type = $_POST['type'];
$message = $_POST['message'];
$formcontent=" From: $name \n Phone: $phone \n Call Back: $call \n Website: $website \n Priority: $priority \n Type: $type \n Message: $message";
$recipient = "contact@6ro.fr";
$subject = "Contact Form";
$mailheader = "From: $email \r\n";
mail($recipient, $subject, $formcontent, $mailheader) or die("Error!");
echo "Thank You!" . " -" . "<a href='form.html' style='text-decoration:none;color:#ff0099;'> Return Home</a>";
?>

<form action="send3.php" method="post">
    <input type="text" name="name" placeholder="Your name" required >
    <input type="email" name="email" placeholder="Your email address" required>
    <textarea name="message" placeholder="Type your message here...." required></textarea>
    
    <div class="recaptcha-holder"></div>
    
    <input type="submit" name="submit" value="SUBMIT">
    
</form>

<?php
session_start();//on démarre la session
// $errors = [];
//On check les infos transmises lors de la validation
  if(!empty($errors)){ // si erreur on renvoie vers la page précédente
  $_SESSION['errors'] = $errors;//on stocke les erreurs
  $_SESSION['inputs'] = $_POST;
  header('Location: contact.html');
  }else{
  $_SESSION['success'] = 1;
  $headers  = 'MIME-Version: 1.0' . "\r\n";
  $headers .= 'Content-type: text/html; charset=utf-8' . "\r\n";
  $headers .= 'FROM:' . htmlspecialchars($_POST['email']);
  $to = 'contact@xxxxx.fr'; // Insérer votre adresse email ICI
  $subject = 'Message envoyé par ' . htmlspecialchars($_POST['name']);
  $message_content = '
  <table>
  <tr>
  <td><b>Emetteur du message:</b></td>
  </tr>
  <tr>
  <td>'. $subject . '</td>
  </tr>
  <tr>
  <td><b>Contenu du message:</b></td>
  </tr>
  <tr>
  <td>'. htmlspecialchars($_POST['message']) .'</td>
  </tr>
  </table>
  ';
mail($to, $subject, $message_content, $headers);
  header('Location: contact.html');
  }

 echo '<p>Thank you for your email!</p>';

<div data-form-alert="" hidden="">Thanks for filling out the form!</div>

if(mail($to, $subject, $message_content, $headers)) {
 $_POST['mail_sent'] = 'yes';
}
  header('Location: contact.html');
  exit();

<?php if ($_POST['mail_sent'] === 'yes'):?>
<div>Hourra !!!</div>
<?php endif; unset($_POST['mail_sent'];?>

$okMessage = 'Contact form successfully submitted. Thank you, I will get back to you soon!';

mail($sendTo, $subject, $emailText, implode("\n", $headers));

        $responseArray = array('type' => 'success', 'message' => $okMessage);
}

if (mail(...)) {
echo '<div>Hourra !</div>';
usleep(Xms);
header(location:...);
}

<?php
session_start();//on démarre la session
// $errors = [];
//On check les infos transmises lors de la validation
  if(!empty($errors)){ // si erreur on renvoie vers la page précédente
  $_SESSION['errors'] = $errors;//on stocke les erreurs
  $_SESSION['inputs'] = $_POST;
  header('Location: contact.html');
  }else{
  $_SESSION['success'] = 1;
  $headers  = 'MIME-Version: 1.0' . "\r\n";
  $headers .= 'Content-type: text/html; charset=utf-8' . "\r\n";
  $headers .= 'FROM:' . htmlspecialchars($_POST['email']);
  $to = 'contact@xxxxx.fr'; // Insérer votre adresse email ICI
  $subject = 'Message envoyé par ' . htmlspecialchars($_POST['name']);
  $message_content = '
  <table>
  <tr>
  <td><b>Emetteur du message:</b></td>
  </tr>
  <tr>
  <td>'. $subject . '</td>
  </tr>
  <tr>
  <td><b>Contenu du message:</b></td>
  </tr>
  <tr>
  <td>'. htmlspecialchars($_POST['message']) .'</td>
  </tr>
  </table>
  ';
mail($to, $subject, $message_content, $headers);
  header('Location: contact.html');
  }