Learn how to code and do it yourselves. Starting a company is a decade-long adventure if you're successful, though timeframes can be significantly shorter if you're unbelievably lucky, it's not something to rely on.
In the long run, learning how to code and making the app yourself doesn't take that much time and significantly improves your chance for success.
If you’re too old and too rich for that shit, then look into the services of a consulting company like the one that I work for. We’ll be happy to take your money and make your app for you. It’s what we do.