The app stores shopping lists and notes locally on your device. To delete all app data:
Android (general steps)
- Open Settings
- Go to Apps → Shopping List & Notes
- Open Storage
- Tap Clear data (and optionally Clear cache)
- Optionally uninstall the app to remove it completely
If you use export/import backups, deleting app data does not automatically delete files you exported elsewhere. Delete those files manually from your storage if needed.