When downloading and installing GTA 5 Mobile Prologue version via APK OBB files, consider the following risks:
Do not download APK or OBB files claiming to be GTA 5. They are almost certainly scams or fan-made demos that could compromise your device's security. HOW TO PLAY GTA 5 ON MOBILE When downloading and installing GTA 5 Mobile Prologue
Since you are not downloading from the Google Play Store, you need to give your phone permission to install apps from other sources. When downloading and installing GTA 5 Mobile Prologue