At present you cannot create the SuperReceptionist account via mobile app.
If you already have your account on the web app then you can login the mobile app with the same account details.
The app will auto-sync all the data that you have on the web app. If you do not have the SuperReceptionist account then you can sign up today for your very own SR account : http://www.knowlarity.com/
You can also get in touch with our support team and they will be happy to help.