If you want to stop syncing for a short time, learn How to pause and resume sync in OneDrive.

If you want to stop syncing a file, read How to stop or cancel sync in OneDrive.

If you want to remove a OneDrive folder from your computer, follow the steps in Choose which OneDrive folders to sync to your computer.

If you just don't want to use OneDrive, the easiest solution is to unlink it.