Is there a specific game engine we need to use, or any guidelines related to how to format and share the game files?
Nope, you can use any engine as long as it can create an app or web build, web build strongly recommended but you can of course also make an app format, please make a mac format if your hardware/softwere supports it.
Hi, I think you missunderstand due to me not really explaining it, you should only make a build for mac if you can, or else windows is totally fine!