Hi, I'm Rodrigo and I will help you.
OneDrive is a cloud storage service, it can sync your files locally and store then on your local storage for faster and offline access.
You can remove the OneDrive local files by right-clicking the files/folder and select "Free up space" this will remove the local copy of the file and only keep it in the cloud.
You can select many files/folders to do it in a batch
The local synced files show the green checkmark and the cloud only files show the cloud icon.