Mail 

$html = \nn\t3::Template()->render('MailTemplate', ['varKey'=>'varValue'], 'tx_extname_plugin');

\nn\t3::Mail()->send([
    'html' => $html,
    'plaintext' => Optional: text version
    'fromEmail' => Sender email
    'fromName' => Sender name
    'toEmail' => Recipient email(s)
    'ccToEmail' => CC recipient email(s)
    'bccToEmail' => BCC recipient email(s)
    'replyToEmail' => Reply to recipient's email
    'replyToName' => Reply to name
    'subject' => Subject
    'attachments' => [...],
    'emogrify' => Convert CSS styles to inline styles (default: `true`)
    'absPrefix' => Convert relative paths to absolute paths (default: `true`)
    'headers' => ['List-Unsubscribe' => ', <https://www.unsubscribe.com>'],
]);