PHPMailer はどのようにして PHP からの HTML 電子メールの送信を簡素化できるのでしょうか?

composer require phpmailer/phpmailer

<?php
use PHPMailer\PHPMailer\PHPMailer;

// Create a new PHPMailer instance
$mail = new PHPMailer();

// Set the sender
$mail->setFrom('[email protected]');

// Set the recipient
$mail->addAddress('[email protected]');

// Set the subject
$mail->Subject = 'Test HTML email';

// Set the HTML body
$mail->isHTML(true);
$mail->Body = '<h2Hello World!</h2>
<p>This is something with <b>HTML</b>formatting.</p>';

// Set the text body (optional)
$mail->AltBody = 'Hello World!!! 
This is simple text email message. ';

// Send the email
if (!$mail->send()) {
    echo 'Mail failed. Error: ' . $mail->ErrorInfo;
} else {
    echo 'Mail sent successfully.';
}
?>