Did it last year, I don't remember exactly what all the questions were since I was a bit distracted at the time (was in Disney World the days the application was open), but there was general get to know you questions and then sample planDisney questions that you could pick from to answer.
The general questions were like occupation, family/household info, past Disney trips, and I think there was one about why you think you'd be good at it. The planDisney questions were very similar to ones you can find on their website, they had a handful to pick from and I think you had to pick two or three to answer. Overall it was very easy, but I don't recommend doing it on your phone, that was a lot of typing on a very small screen last year! You can save and come back to finish later (or at least could last year).
If you're going for it, good luck!