A document that shared power between the king, nobles, and vassals-forcibly signed by the king would be the Magna Carta. This was also called the "Great Charter", signed in 1215 and limited the King's power.
A set of laws all English citizens followed would be Common Law. This was based on court rulings and set a way of life for the English Citizens.
The English Parliament was divided into 2 branches, House of Lords and House of Commons.
The Doomsday Book was created to take a census of the people, manors, and animals after he conquered the land. This was after William of Normandy took the land.
The French Parliament was divided into 3 branches, estates, clergy, nobles, and the townspeople.