Magento doesn’t have default functionality to stop sending newsletter emails.
Below I show an example of how to disable newsletter subscription emails.
Create a custom module and add di.xml
Override Subscriber.php
app/code/Vendor/Module/etc/di.xml
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
<type name="Magento\Newsletter\Model\Subscriber">
<plugin name="myplugin" type="Vendor\Module\Newsletter\Model\Subscriber" sortOrder="1" disabled="false"/>
</type>
</config>
Now create Subscriber.php
app/code/Vendor/Module/Newsletter\Model\Subscriber.php
<?php
namespace Vendor\Module\Newsletter\Model;
use Magento\Newsletter\Model\Subscriber as SubscriberModel;
class Subscriber
{
/**
* @param SubscriberModel $subject
* @param callable $proceed
*/
public function aroundSendConfirmationRequestEmail(SubscriberModel $subject, callable $proceed) {}
/**
* @param SubscriberModel $subject
* @param callable $proceed
*/
public function aroundSendConfirmationSuccessEmail(SubscriberModel $subject, callable $proceed) {}
/**
* @param SubscriberModel $subject
* @param callable $proceed
*/
public function aroundSendUnsubscriptionEmail(SubscriberModel $subject, callable $proceed) {}
}
Now run following commands
php bin/magento setup:upgrade
php bin/magento setup:di:compile
php bin/magento cache:clean