Third-party apps on Shopranos can securely access store data using OAuth-based authentication. Each app is provided with a Client ID and Client Secret upon creation, which are essential for obtaining an access token. This token, combined with the Company ID received during the app installation process, allows the app to access and interact with Shopranos data. Access is governed by the permissions approved by the store owner, ensuring secure and controlled data management for both the app and the store.