This tutorial explains how to make a file, document or folder stored on Google Drive available for offline reading or editing on your smartphone. The procedure is the same for both the Google Drive client for iOS and Android.
Make sure that your smartphone or tablet is connected to the internet and launch the Google Drive app. Navigate to the file or folder you want to make available offline and then tap on the small exclamation mark displayed next to it:
Toggle the Keep offline switch on:
That's it; the selected file is now available for offline reading or editing on your mobile device. To view your offline files: Tap on the Menu button > Offline: