After installing the extension on Magento, if the installed Extension is not visible or is not working properly then you can try Refreshing the Cache from Magento Admin. You can do it via ssh/terminal (CLI) or can do it from admin panel.
- Via SSH/Terminal CLI Run this command into CLI: php bin/magento cache:clean
If it doesn't solves the problem, run: php bin/magento cache:flush
- Via Admin Panel To refresh the cache from admin panel, follow these steps: Log into Magento Store Admin Panel Navigate to System ⇒ Cache Management. Now select all the cache types in the list, choosing the refresh option in the drop down menu , and finally click on submit button.