How does My World PE transform the creative mode into the survival mode?

First, open your game and click "Start" to come to the world selection interface. Then you will find a "0" button on the right side of each map and click it. You will find an interface similar to the following:

As you can see, the two boxes below the game mode:

If your version is China, "survival" means survival, and "creativity" means creation.

Click "survival" and then click "back" to open the map, and you can find that your map game mode has become survival mode.