A crime scene is the specific area where a crime took place. Crime scenes can be nearly anywhere.
In the context of the law, crime scenes are often investigated in an effort to try to find evidence. Evidence that is found in crime scenes can be used in a court of law if it is procured legally.
Crime scenes can exist for more severe crimes such as murder, and they can also occur for less severe crimes such as vandalism.
If law enforcement wants to collect forensic evidence from a crime scene, then they send in crime scene investigators who have special training in collecting such evidence. Any forensic evidence that is discovered at the scene of a crime can be handed over to the prosecution. The prosecution can then use this evidence to implicate the defendant.