
In order to save hard drive space on your PC, please do the following.
When you "Free up Space" you are not deleting the files, you are simply keeping the files on the cloud which will still be accessible to you once you open them.
They will automatically download and open.

Using Windows Explorer, navigate to your OneDrive and SharePoint files.
1.- Click on OneDrive or SharePoint
2. Right mouse click on a Folder that shows it is always on the device.
(Green Icon)

3. Pick "Free up Space"
The files will remain accessible to you, there will be uploaded to the cloud and removed from your local drive.
You will still see them but they will be downloaded when needed saving valuable space on your local hard drive.
See image below: