You write a single set of source and you can build that source for:
- Android
- iOS
- OS X
- Windows 32
- HTML5
- Apple TV
- Android TV (really just Android)
You do all this building from the Corona simulator. https://docs.coronalabs.com/guide/distribution/
For iOS builds, it is required you build using the OS X version of the simulator and that you have the correct xCode installed, because there are steps required by Apple where the simulator must use xCode resources to do some of the work.
For Android builds, you can build on OS X or Windows machines, using the corresponding Corona simulator. To sign and build, you must have the correct JDK installed. xCode is not used for Android builds.
https://docs.coronalabs.com/guide/distribution/androidBuild/index.html
Once you have the correct tools installed, builds are easy and initiated from the Simulator.
What About Corona Native?
This is an alternate way of building that I won’t discuss here since this is in the newbie forums. I will only say, that if you find you need to add specific native features to Corona that it doesn’t already support, you use the Native build process to do that.
https://docs.coronalabs.com/native/index.html