Each mobile version (iOS, Android, and Amazon) is a separate purchase from each other, and from the PC/Mac version, due to App Store requirements and other factors out of our control. So:
If you purchase the game for computer (on wolfquest.org or itch.io or Steam), you can download it for Windows or Mac OSes.
If you purchase it from the Apple App Store for iOS, you can download it to any iOS device (iPhone or iPad) that has your Apple ID.
If you purchased it from the Google Play Store, even though the game is no longer available, you can download it to any Android device that has the Google Play Store app with your Google ID.
Then, after creating an account, you can log into the game on any of the above devices and sync up your data.
Note: WolfQuest does not run on Chromebooks.