Europa is one of the smoothest objects in the Solar System. Although there are many surface features, including craters, these are few and far between. It is believed that Europa’s surface is a series of brittle tectonic ice plates moving on top of a warmer layer of convecting ice. Beneath that is probably a subterranean ocean of water.
Recent observations have shown these icy tectonic plates moving about, creating ice plumes and ‘cryolavas’ in a mechanism akin to volcanism on Earth. This constant recycling of the surface material means that craters and other features don’t survive for very long.