Others can't see the whole world

I worked on big world in creative mode last summer and Im hoping to get it done by July 4. Whenever I visit that world on my iPad everything is perfectly fine, but anytime someone else joins they can't see the whole thing. My device is the only one that can see the whole world. Other devices can't see all of the sides. The world doesn't expand all the way for them. I took a picture of what other people see on their device. Please help!!!