phpcms sendmail

<?php
$to = "recipient@example.com";
$subject = "Test Email";
$message = "This is a test email sent using PHP's sendmail function.";
$headers = "From: sender@example.com";

if (mail($to, $subject, $message, $headers)) {
    echo "Email successfully sent.";
} else {
    echo "Email delivery failed.";
}
?>

<?php
require 'vendor/autoload.php';

use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\Exception;

$mail = new PHPMailer(true);

try {
    // Server settings
    $mail->SMTPDebug = 0;                      // Enable verbose debug output
    $mail->isSMTP();                                            // Send using SMTP
    $mail->Host       = 'smtp.example.com';                     // Set the SMTP server to send through
    $mail->SMTPAuth   = true;                                   // Enable SMTP authentication
    $mail->Username   = 'user@example.com';                     // SMTP username
    $mail->Password   = 'password';                               // SMTP password
    $mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;         // Enable TLS encryption; `PHPMailer::ENCRYPTION_SMTPS` encouraged
    $mail->Port       = 587;                                    // TCP port to connect to, use 465 for `PHPMailer::ENCRYPTION_SMTPS` above

    // Recipients
    $mail->setFrom('from@example.com', 'Mailer');
    $mail->addAddress('recipient@example.com', 'Joe User');     // Add a recipient

    // Content
    $mail->isHTML(true);                                  // Set email format to HTML
    $mail->Subject = 'Here is the subject';
    $mail->Body    = 'This is the HTML message body <b>in bold!</b>';
    $mail->AltBody = 'This is the body in plain text for non-HTML mail clients';

    $mail->send();
    echo 'Message has been sent';
} catch (Exception $e) {
    echo "Message could not be sent. Mailer Error: {$mail->ErrorInfo}";
}
?>