Google Drive Now Sends Sharing Notifications on Mobile Devices
Android / iOS: While Google Drive is great for file sharing, it has always been a little more cumbersome than on a mobile device. Things are now changing with notification sharing and additional mobile features.
The latest version of Google Drive, which is currently rolling out, will send a notification to your phone when you are given access to a file. It should be much easier than a regular email notification. You can also receive a notification when a user requests access to a file. Finally, Google allows users to preview the Google Drive files they have permission to view on Android without having to select a Google account. This should bring it in line with how it works on the desktop.
Because sharing files should be easy | Google Drive Blog via Android Police