When an asteroid or meteoroid space object hits a planet, or a planet's atmosphere, the effect can vary considerably depending on factors like size (of both the planet and asteroid), speed, composition/density and angle of entry.
Meteoroids are usually defined as being smaller rocky objects (usually less than 10 metres) they become meteors when they enter the Earth's atmosphere. Some meteors may disintegrate or may bounce off the surface or be at angle to pass through without impacting. This causes them to glow or burn up .
Sometimes parts of a meteoroid will break up and land on the surface. These are pieces are called meteorites (the ending _ite indicates a type of rock).
An asteroid can break up into smaller parts each individually becoming meteors. Most meteoroids don't make an impact crater due to their small size and braking effects of the atmosphere.
Large meteors can still create significant shock waves (due to passing the sound barrier on entry of the atmosphere) and fire balls ( an airburst) in the atmosphere but leave no significant impact crater. Trees may be blown down e.g. the Tunguska Event.
A larger asteroid has the potential to cause an impact crater and a major natural disaster.
In addition to extreme effects of ejected materials and tsunamis (recent simulations show that the tsunami would only occur very close to impact e.g. sudden wall of water would be ejected upwards) , if a crater is formed due to an asteroid impact the crater can be either simple or complex depending on the size and angle of impact.
Interestingly, the complex crater has features similar to wave patterns formed when an asteroid hits the surface of the ocean.