Your Minecraft account and saved worlds are separate things. Signing in does not mean every world on your Android device is automatically backed up. Before changing phones, reinstalling Minecraft or trying new content, check where your worlds are stored and which backup options your version provides.
Create a backup you can use
Open the world settings and look for the copy or export features available on your platform. Keep the original and give the backup a recognisable name with a date. A copy inside the same app can help you recover from changes to a world. It may not protect against losing your phone or deleting the app data, so check the supported transfer method as well.
Check a transfer before deleting anything
- Read the official instructions for your Android version and Minecraft edition.
- Check that both devices have enough storage for the transfer.
- Open the transferred world and inspect important buildings, inventories and chests.
- Keep the original until the world works properly on the new device.
Avoid following old folder paths without checking them: Android storage access has changed over time. If you use Realms, review its world download and backup options before replacing an existing world.
Learn more: Official Minecraft Help Center.