According to this CBR article:
Characters and locations from Disney films and theme parks will be art of a new universe, and the first project is entitled "The Society of Explorers and Adventurers".Ron Moore (Battlestar Galactica, For All Mankind) is bringing his creative talents to Disney+ to launch a franchise of streaming projects centered in what is being billed as a Magic Kingdom Universe.
My impression is that the society will visit landmarks and locations, and meet the characters that live there, from various movies and theme parks as it globe trots. So for example, we can see all the kingdoms of the Disney Princesses, as well as Arendelle, co-existing in a single world as they are depicted in their respective feature films.