Convert my current web Site to App

I run a service-booking website and now need to convert that website in Android and iOS versions. The core content and workflow already exist on the web; what I’m after is a smooth wrapper or rebuild that keeps the current experience intact while feeling like a true mobile app.

Key requirements
• Users must be able to sign in and manage their bookings exactly as they do online (standard email/password plus any social logins already live).
• Real-time push notifications are essential for confirmations, reminders, and status updates.

Beyond the coding itself, I’d like your help generating production builds and guiding me through publishing the Android release on Google Play. If you can also prepare the iOS build for App Store submission, let me know—having both platforms ready at launch is the goal.

I will provide site URLs, existing API endpoints, brand assets, and access to my developer accounts as soon as we start. Please include a brief note on which framework you plan to use, estimated timeline, and any app store requirements I should prepare for.