A Microsoft file hosting and synchronization service.
The feature is not there any longer and there are multiple threads in this forum which talk about this.
I'm in Windows Explorer, looking at folders and files in OneDrive. Used to be when you right-clicked on files or folders in OneDrive you had multiple selections regarding the files and their physical locations. One was "Always keep on this device" which did exactly that; made a physical copy on the device's drive, so if you were disconnected from the internet, you could still access the file. Another was "Free up space on this device" which would remove the file from the local device but keep it in the cloud. Both of those choices are gone now. Both of these are extremely useful to me and now that they are gone I only have a choice of removing the files from OneDrive and putting them on the local device. Which of course defeats the purpose of OneDrive which is that our files are available whereever we can find internet.