With Drive File Stream, you stream your Drive files directly from the cloud to your Mac or PC, freeing up disk space and network bandwidth. Because Drive files are stored in the cloud, any changes you or your collaborators make are automatically updated everywhere. You’ll always have the latest version.
You can also make Drive files available for offline access. These cached files sync back to the cloud when you’re online, so the latest version is available on all your devices.
With Drive File Stream, you can:
Quickly see Drive files in Finder/Explorer.
Browse and organize Drive files without downloading all of them to your computer.
Choose which files or folders you’d like to make available offline.
Open files in common apps like Microsoft Office and Adobe Photoshop.
More information and support is available at https://support.google.com/drive/answer/7329379