You can visit only one theme park a day until January. Park Hopper ticket options, which let guests visit multiple parks on the same day, are being sold online, but you won’t be able to use Park Hopper until next year. Starting Jan. 1, 2021, guests with the Park Hopper ticket option or an annual pass with Park Hopper benefits will be allowed to visit more than one park per day after 2 p.m.
Disney says park reservations will be required for the first park but not the second, though this may change in the future. To learn more, visit the park's website.