I did google how to do it, I found one solution online https://www.metagento.com/blog/magento-2-disable-newsletter-subscription-success-email
however I don't know why I can't install, I did check the module status, it not showing in the list. even I follow from their website, still no success.
php bin/magento setup:upgrade php bin/magento setup:static-content:deploy php bin/magento cache:flush
can anyone tell me how to get this thing install?