Quick Answer: Stable is safest for servers and Realms, Beta is for testing only, and Trial is free and time-limited.
Stable version: Stable is the tested release for everyday play. Choose stable if you play regularly, use servers or Realms, or want the fewest surprises. Check the Google Play listing and the official Mojang changelog for the current stable build.
Beta / Preview version: Beta and Preview builds give early access to new features, but they may be unstable and may break worlds or add-ons. Use beta only for testing, back up your worlds first, and do not use it as your main game if you play on servers or Realms.
Minecraft Trial: The Trial is free and time-limited, and covers Survival mode. After the limit, your world remains viewable.
How to choose: Everyday play — choose Stable. Early features — choose Beta. Test before buying — choose Trial. Server or Realms — choose Stable matching the server.
Safety checks: Check that the package name is com.mojang.minecraftpe and that the signature matches Mojang. If you get a signature conflict, uninstall the existing Minecraft build first, then install again. Back up your worlds before switching versions.
Related guides: Minecraft APK homepage — https://minecrftdownloads.com/ ; Minecraft for PC guide — https://minecrftdownloads.com/minecraft-free-download-pc/ ; Minecraft Java Edition guide — https://minecrftdownloads.com/minecraft-java-edition/ ; Minecraft for iOS guide — https://minecrftdownloads.com/minecraft-download-ios/