Magna Carta (1215; revised 1297)
A group of rebel barons presented a list of
demands to the king, declaring that..
Amdmt For a trivial offence, a free man
shall be fined only in proportion to
the degree of his offence, and for a
serious offence correspondingly, but
not so heavily as to deprive him of
his livelihood.
What's this amendment?

Eighth Amendment.

Explanation:

For the Founding Fathers' of America, Magna Carta was a great inspiration for the protection of natural rights of man and symbolized liberty to citizen. While drafting the Constitution, the Declaration of Independence, and the Bill of Rights, the Fathers took great inspiration from Magna Carta.

The amendment which mirrors the 20th Clause from the Magna Carta is Eighth amendment. The Eighth Amendment of the Constitution also prohibits charging excessive bail from the criminal defendants. The amendment forbids the government from charging harsh penalties from the criminal defendants either as a price for pretrial release or as a retribution after being convicted.

Therefore, the answer is eighth amendment.

both include an amendment process.