A BIG change happened when Disney World reopened in 2020 and guests were introduced to the park pass reservation system.
That system has stayed in place, and it seems like it’s going to be around for at least a while longer. So Disney World guests now must have a valid ticket PLUS a reservation for a park for a specific day (although they can hop to another park later without a reservation for THAT park). Now, how that reservation is made looks a little different on the My Disney Experience app.