Sites offering APK and OBB files for this game are often misleading or unsafe. Here is the factual status of the game and how you can actually play similar titles on your mobile device. The Reality of Forza Horizon 3 on Android Official Platforms: Forza Horizon 3 was released only for PC (Windows)
While you cannot install the game directly, you can play Forza titles on Android through official services: forza horizon 3 android apk obb download new