I have created a simple "hello world" module in Magento(2.2.1) and seems to be working fine. http://35.224.126.44/magento/helloworld/index/test
But I am not able to find the installed module in the admin panel. Please let me know how to check installed modules through admin panel. As I don't see an "Advance" option inside store > configuration > Advance >?
From Magento version 2.2 on, the Advanced Menu is not available.
Though you can manually check/enable/disable modules from app/etc/config.php file or can use following commands:
php bin/magento module:disable -c -f [CompanyName]_[ModuleName]php bin/magento module:enable -c -f [CompanyName]_[ModuleName]