EventManager::registerEventHandler

public function registerEventHandler($entity, $eventType, $toModuleId, $toClass = "", $toMethod = "", $sort = 100, $toPath = "", $toMethodArg = [])
{
	$entity = static::obtainEntity($entity);
	$eventType = static::obtainEventType($entity, $eventType);

	// subscribe
	\Bitrix\Main\EventManager::getInstance()
		->registerEventHandler($entity->getModule(), $eventType, $toModuleId, $toClass, $toMethod, $sort, $toPath, $toMethodArg);
}