The Magna Carta is a charter agreed to by King John of England at Runnymede and rebel barons.
It pledged the protection of the rights of the church and for the barons from illegal imprisonment, but neither King John nor the barons could respect the promised agreements and the charter was later annulled.
Habeas Corpus was used (and still is) when a person reveals what they think was a wrongful imprisonment to the King. The prison official then decides if they think their imprisonment was just or not.
Today we use trial by jury as a fair way for a jury to make a decision. We use common law for judges to decide individual cases, they are also for future cases. The Magna Carta is still in use today, it gives people right to justice and to a fair trial. The Parliament makes laws today. Habeas Corpus is not in use today. Independent Judiciary is the same today as it was in the medieval ages, it separates the judiciary part of the government from the rest.