All my worlds on Minecraft pocket edition on iPad are creative, is there anyway I can change them to survival?
There is one way... You just need access to the iPads file system. This can be done by jailbreaking and installing iFile, or you can install phone explorer for your computer. Then you go into /var/applications/minecraftPE/documents/Minecraft Worlds.
On your device, go into minecraft and make a new survival world. Call it something different to all your other worlds.
Refresh Phone explorer then go into the folder that has the name of the minecraft world you just created. Delete the "chunks.dat" and go back to your minecraft worlds.
Then go into the creative world folder which you want to change to survival, and copy the "chunks.dat". Go back into the survival world and paste the file.
On your device, close minecraft propperly, then open again. Go into the survival world you made and your creative world will be there. (somewhere)
Sorry it's all a bit complex but it's the only way I know.
No, there is currently no method to change gamemodes in minecraft PE. Although, in minecraft PE 0.7.0, the basic command structure was implemented, unfortunately no commands were added. If you want survival worlds, create a new world in survival mode. Hope this helps!
An easy way is to chose the world you want to edit go to where you pick the world and then there is an pencil icon on the world you want change click it and it will say survival and creative so you click creative and click back and magic
Get the world on your computer and change it there.