Before heading to Walt Disney World, I recommend downloading several FREE apps, which will help make your life a little bit easier while on vacation. Wherever required, set up account with usernames and passwords PRIOR TO when your vacation starts, this way when/if you need to use the app while on vacation, you will be prepared and ready to go!
First and foremost, please make sure you download the My Disney Experience app. This app provides your reservation information, dining reservations, fast pass reservations, attraction and bus wait times, and more! This app, of all on the list, is the most critical (in my opinion).