Briefly describe two ways to formally amend the constitution

Formal method of amending the Constitution

An amendment can be proposed by two-thirds of both houses of Congress or

By two-thirds of state legislatures requesting Congress to call a national convention to propose amendments.

An amendment can be ratified by a favorable vote in three-fourths of all state legislatures or by such a vote in specially called ratifying conventions called in three-fourths of the states.

PS : This is for the US constitution, don't know if it differs for other countries.