Mobile App (open-source if possible)

Hello, I am interested in hiring you to develop an app for bakeries. The app will have four menu items: Home, Discounts, Order, and About. The "About" menu should be connected to a website section so users can view the website without leaving the app. The "Discounts" menu should be managed by the bakery owner, who will be purchasing the app from me. The owner should be able to post deals for customers to see, including the period of the deals and the applicable items. I'm not so sure about the "Home" menu (just leave it for now), and the "Order" menu will allow customers to place orders through the app. To ensure security, customers will need to create an account using their phone number and receive a verification code. The bakery owner should be able to block numbers from ordering. Can you please let me know if you can complete this project? Also, what would be your estimated cost and timeframe for completion? Please note that the app will be sold to bakery owners who will manage their own discounts, so can you provide an option for bakery owners to manage their own deals? and I want the app to be available on both, android and IOS devices. Thank you for your time, and I look forward to hearing from you. (that is just an idea of the app, don't make anything, yet) Best regards, mhn7