https://www.cnet.com/news/disney-star-wars-land-opening-date-two-phases-may-california-aug-florida-galaxys-edge-everything-we-know/

If you want to be the very first to experience Galaxy's Edge at Disneyland, you'll need to make a reservation. Between May 31 and June 23, a Disneyland park ticket alone won't get you in -- guests will need to make a reservation to access the Star Wars section of the park. It won't cost extra but there will be limited availability, and guests staying at one of the three Disneyland Resort hotels during those dates will get a reservation to access Galaxy's Edge. In a blog post, Disney says more details on how to make a reservation will be announced later. 

Disney says no reservations will be required for the Disney World version opening in August, but capacity will be limited.