Build Mobile App from Telegram Barcode Bot (Python)

Description

The program currently exists as a telegram bot coded in Python - the user uses a command containing a store name and an item barcode number (e.g. /tesco 4125417485021), and the bot processes the input and generates a new barcode based on the store's set formula. For example, Tesco = "975(user_input)000001" so the new barcode would be 9754125417485021000001.
I can provide a screen recording demonstrating the telegram bot, and if we work together, I will provide the source code containing the formulas for each store.
Essentially I want to convert the bot into an app that will:
Authenticate users with a username and password and ensure only one device is able to use the app at a time
Allow users to enter a barcode number or scan an existing barcode and use this as the input
Allow users to choose a store from a list of options
Process the inputted number based on the store’s formula
Output a new barcode
Save generated barcodes to the user's account so they can view them within the app
Enable users to rename saved barcodes
Enable users to sort saved barcodes by store name
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The app should work with iOS and Android and enable the admin to manage user accounts via database.