Hi I was just wondering are we aloud to use any game engine we want, because one of the only game engines I use only exports to an .APK file which is used by android mobile devices. Are we aloud to export to a .APK file? If we aren't aloud to use a .APK file what export files can we use?

Yes, you can use any game engine you'd like.

Any export file?

Yes, any will do I think. :)

As long as it will upload to itch.io it's allowed, the only issue is if you're not exporting in an exe file or something which can be played in browser, you're likely to get much fewer plays.