In the Minecraft Pocket Edition, you can create a backup of your world. You have to zip the files of your world and put them in a new folder. So if you accidentally delete your Minecraft folder or game, you still have your world files on your phone. To backup your world, you have to move the zip files to the Minecraft folder. You can even send your world to your friend or move it from one phone to another.
Firstly, you will need to download the ZArchiver Pro app on your phone. You can even use the compress option if it is available on your phone. Now go to the games folder and move to minecraftWorlds.
You will find the worlds in this folder.
Now select all of them and click on the Compress option.
Now you will need to choose the Compression Level. The Ultra option is recommended.
After that, move the zip file to the New Folder. You can even create a backup in your Google Drive.
Now, if you accidentally deleted your worlds, you have to extract your zip files in that Minecraft folder.