Apple has partially switched on the iCloud switch starting with the App Store on all iOS devices. You can know familiarise yourself with the new features Apple has added by going to your "Updates" section in the App Store which adds a new "Purchased" tab, revealing a history of all the apps you've downloaded with your account thus far. Apps with the iCloud icon are presently not installed on your device. You can choose to install any of the apps you previously purchased or got for free and re-download them again for free. If you're not seeing the new changes, fully close your App Store and re-open it to see the new changes.