TreeHugger's article, "What Causes Waves in the Ocean? Energy Analysis and Wave Types" explains that "A wave forms whenever energy passes through a body of water, thereby causing the water to move in a circular motion"(Means). This energy that moves the ocean around is what is known as a disturbing force. As you move down into the wave, this energy is slowly lost, making this circular motion of water smaller as you go down. 

There are two main types of waves: free waves and forced waves. The Geophile Pages explains in their article "Wave Basics," the difference between free waves and forced waves. Free waves are able to "move without any further influence from the force that created them"(Leyva). An example of a free wave would be wind waves, which rely on wind to get them moving, but not to sustain them. For forced waves on the other hand, "movement is dependant upon the force that creates them"(Leyva). An example of a forced wave would be tides that are dependent on the gravity of the moon to move. Another type of wave is one created by sisemic activity. Tsunamis are an example of this type of wave.