In order to compile and build our application to an Android or IOS application you may required to open an account on the Expo.
This account is necessary to compile our app's react native code. As on the local pc we can only code and see the preview of the app but we can't really run build on the device. Expo have highly powered servers and technology to compile the app. So, when our code is ready when need to push our app code to official expo's website and they will compile it for us depending on which platform we need.
Next if you want to enable push notifications in your apple you will be needing and OneSignal account. If you don't have an OneSignal account then please Register For a new account. But OneSignal is optional and you only need OneSignal account if you wish to enable push notifications.
Now after have code editor installed on the pc we can move on the Configurations