Mobile App: Once you uninstall the JioCloud app, your files remain safe in JioCloud account. But your backup settings get reset which means you need to set your backup settings again when you install the app again.
Desktop App: Once you uninstall desktop app, your JioCloud folder created on desktop still remains with all the files synced in it. To completely remove JioCloud from your desktop, delete JioCloud folder as well after uninstalling the app.