Add sendMail method to ActiveRecord class.

Records.php

<?php

class Records extends \yii\db\ActiveRecord
{
 const EVENT_SEND_EMAIL_UPDATE = 'send-email-to-users';
 public function init() {
   $this->on(self::EVENT_SEND_EMAIL_UPDATE, [$this, 'sendMail']);
   
   //use this if you want to add custom data to your events
   $this->on(self::EVENT_SEND_EMAIL_UPDATE, [$this, 'sendMail'],['Email 1','Email 2','Email 3']);
   
   parent::init(); 
 }
 public function sendMail($event) {
    //if you had attached some data you can use this to get the event data
    $customData = $event->data;
 //send email to subscribers
    
 }
}