namespace app\commands;
use yii\console\Controller;

class MailController extends Controller {

    public function actionSend() {
       // Code here to send the mail
       // Example details: http://www.yiiframework.com/doc-2.0/yii-swiftmailer-mailer.html
       Yii::$app->mailer->compose('contact/html', ['contactForm' => $form])
          ->setFrom('from@domain.com')
          ->setTo($form->email)
          ->setSubject($form->subject)
          //->setTextBody($this->body)  // optionally set data here
          ->send();
    } 
    ...
}