This CodeLet Sends an email after a node of specific content type is created. The CodeLet uses Drupal8 API which sends and email upon node creation. This CodeLet implement hook_entity_insert & hook_mail.
Place this CodeLet on your MYMODULE.module file. 

CodeLet
<?php
//Add this line to the top of the MYMODULE.module file.
use Drupal\Component\Utility\SafeMarkup;



/**
 * Implements hook_mail().
 */
function MYMODULE_mail($key, &$message, $params) {
   
$options = array(
           
'langcode' => $message['langcode'],
    );

    switch (
$key) {
        case
'node_insert_alert':
           
$message['from'] = \Drupal::config('system.site')->get('mail');
           
$message['subject'] = t('Ticket created: @title', array('@title' => $params['node_title']), $options);
           
$message['body'][] = SafeMarkup::checkPlain($params['message']);
            break;
    }
}

/**
 * Implements hook_entity_insert().
 */
function MYMODULE_entity_insert(Drupal\Core\Entity\EntityInterface $entity) {
   
    if (
$entity->getEntityTypeId() !== 'node' || ($entity->getEntityTypeId() === 'node' && $entity->bundle() !== 'CONTENT_TYPE')) {
        return;
    }
   
       
$mailManager = \Drupal::service('plugin.manager.mail');
       
       
$module = 'MYMODULE';
       
$key = 'node_insert_alert';
       
$to = 'To mail '; // email to be sent to this Email ID
       
       
$params['message'] = "Message";
       
       
$params['node_title'] = $entity->label();
       
$langcode = \Drupal::currentUser()->getPreferredLangcode();
       
$send = true;
       
       
$result = $mailManager->mail($module, $key, $to, $langcode, $params, NULL, $send);
        if (
$result['result'] !== true) {
           
$message = t('There was a problem sending alert email notification to @email for creating ticket @id.', array('@email' => $to, '@id' => $entity->id()));
           
//drupal dblog
           
\Drupal::logger('MYMODULE alert')->error($message);
            return;
        }
       
       
$message = t('An email notification has been sent to @email for creating node @id.', array('@email' => $to, '@id' => $entity->id()));
       
//drupal dblog
       
\Drupal::logger('MYMODULE alert')->notice($message);
}
?>
Compatibility
Submitted by saru1683 on