"There is no requirement that police stop a person who enters a police station and states that he wishes to confess a crime or a person who calls the police to offer a confession because volunteered statements of any kind are not barred by the 5th Amendment"

This quote by Earl Warren is referring to the Fifth Amendment of the United States Constitution, which mentions that no individual will be obliged to be a witness versus themselves in any criminal case. This indicates that the authorities can not force an individual to admit to a criminal activity. Nevertheless, this does not imply that a person can not willingly admit to a crime. If a person enters a police headquarters and states that they want to confess a crime, or calls the police to offer a confession, there is no requirement that the cops must stop them. The Fifth Amendment does not bar volunteered declarations of any kind, so the police are not restricted from accepting a confession. This quote is highlighting that a person deserves to confess to a criminal offense without being required to do so.