A Microsoft file hosting and synchronization service.
Files in OneDrive are stored in the cloud at onedrive.com and also in your computer's OneDrive folder, located at ThisPC>C:>Users>username>OneDrive.
Do not delete any files in OneDrive unless you intend to get rid of them. Instead, turn off folder backup in the Manage Backup settings. After backup has been disabled, move your files back to their default locations in File Explorer.
Manage your OneDrive backup preferences in Manage Backup: https://support.microsoft.com/en-us/office/back-up-your-folders-with-onedrive-d61a7930-a6fb-4b95-b28a-6552e77c3057