In order for the app to appear in the App Stores, it will need to go through a store submission process.
Your app will be submitted to the App Store and Play Store for approval. The approval process for each system is slightly different.
Apple generally aims to review and approve a new app within 24-48 hours. Once approved your app will be available for release.
Google's approval process is generally completed within a few hours of submission.
Find out more about the Launch Process and next steps here.