What resources or tutorials are recommended for beginners in PHP to understand and address common issues like special characters and email sending?

Special characters can cause issues when sending emails through PHP, as they can interfere with the email's formatting or cause errors in the email body. To address this, it's recommended to use PHP's `mb_encode_mimeheader()` function to properly encode special characters in email headers.

$subject = 'Subject with special characters éàü';
$subject = mb_encode_mimeheader($subject, 'UTF-8', 'Q');