Transform-fault boundaries are created when two tectonic plates slide past one another horizontally, according to the website Plate Tectonics. They are also known as transform boundaries or more commonly are called faults. A transform boundary is also known as a conservative plate boundary because it neither creates nor destroys lithosphere. Most faults are found on the ocean floor.
Most faults commonly offset active, spreading ridges that produce zig-zag plate margins, and are defined by shallow earthquakes. There are a few that occur on land, and the most popular is the San Andreas fault. It is a fault that is about 1,300 kilometers long and, in some places, can be tens of kilometers wide and runs through about two-thirds of California. All along this fault the Pacific plate has been grinding against the North American plate for 10 million years, moving at a rate of about 5 centimeters per year. The Pacific plate is moving northwest, and the North American plate is moving southeast.
There are three types of boundaries. A divergent boundary is when two or more plates pull apart or diverge, creating new crust. Divergent boundaries are where oceans open or made wider. There are convergent boundaries, where plates come together, forcing one plate under the other and is recycled to the interior of the Earth. This is often where volcanoes and mountains are formed.