Can I show my ticket on my phone or do I need to print it out?

From Prekindle Help

For fastest entry, it is best to have your ticket printed out.

The resolution of your phone's screen, and the amount of light at the gate can make it difficult to scan a ticket from your phone. For a big event, there may be many people trying to access cellphone networks, and you may have trouble pulling up your ticket on your phone.

If the door staff is unable to scan your ticket from your phone, you will be directed to the Box Office to acquire a physical copy of your ticket, then you can return to the door staff to have it scanned.