In PHP's official manual, for mail function an example is given like:
$to = 'johny@example.com, sally@example.com';
$headers[] = 'To: Mary <mary@example.com>, Kelly <kelly@example.com>';
..
mail($to, $subject, $message, implode("\r\n", $headers));
What's difference between giving recipient's email address in header vs in $to above? Which one should i use?