High fantasy is a sub-genre of fantasy fiction. It is also called epic fantasy. High fantasy is normally set in fictional universes. These universes are created for the story or stories. High fantasy is not set in the real world.
Examples of high fantasy include The Lord of the Rings by J. R. R. Tolkien. A Song of Ice and Fire (Game of Thrones) by George R. R. Martin, the Discworld series by Terry Pratchett and The Wheel of Time series by Robert Jordan.