Most of these words are interchangeable depending on what you are trying to say. travel - to cover the distance between two points trip - trip usually suggests that there will be some enjoyment or entertainment while travelling (unless it's a business trip) voyage - this typically has a more grandiose meaning, similar to journey tour - a tour is a guided trip around a certain place, such as a tour of a museum or a farm journey - journey is yet another way to indicate travel from one place to another (or perhaps several places)

In addition, you can use "voyage" when you want to go to moon by space ship or to some destinations by ship.