Heaven, in the movie's continuity, is a region of the Afterlife.
In the movie, Heaven is where virtuous souls naturally go when they die (while evil souls are taken to Hell instead). Remaining on Earth as a ghost, in this continuity, is an abnormal destiny, which only arrives in presence of a Curse, which is most often caused by an unpunished earthly crime or otherwise unsolved mortal issue, which the souls must deal with before they can move on to either Heaven or Hell.
Heaven seems located “above” Earth, and when the souls move on, they do not retain a human-like body like ghosts but instead turn into orbs of light (which however seem to retain the ability to talk and sense the world around them).
- There is no evidence that either Heaven or Hell even exist in the ride's continuity.