Do you have to pay separate to go all the Disneyland areas?

There are several areas in Disneyland, and they are all covered by your admission. However, there are several separate theme parks that are owned by Disney. Epcot, Animal Kingdom, and Universal Studios each require either their own ticket or a Park Hopper pass. The Park Hopper costs just a little extra, but it allows access to all the parks for the duration of your trip.