With OneDrive Files On-Demand,you can get to all your files in OneDrive or SharePoint Online, without havingto download them and use storage space on your device.
Note: With Windows 10 version 1809 and later, Storage Sense is available to automatically free up disk space by making older, unused, locally available OneDrive files be available online-only.
If you’re on Windows 10, your computer already has the OneDrive desktop app on it, but you'll need to turn on Files On-Demand in OneDrive settings:
When Files On-Demand is on, you’ll see new status icons next to each of your SharePoint files. You can now copy or move files from your computer to SharePoint Online straight from your file system.
Save space on your device by making files online-only. These files are only available when you're connected to the Internet, but don't take up space on your computer.
When you open an online-only file, it downloads to your device and becomes locally available. You can open a locally available file at anytime even without Internet access.
To make a file always available, even when you're offline:
To change a file back to an online-only file: