what majority vote for an amendment to the constitution may be proposed by the congress
An amendment may be proposed by a two-thirds vote of the House of Representatives and the Senate or a national convention called by Congress at the request of 2/3 of the state legislatures. The latter procedure has never been used.
The Constitution may be amended according to the following process. First, an amendment must be proposed, and then, ratified. An amendment may be proposed by a majority vote of both houses of Congress, provided that no Amendment Convention is active.