Who Created the Constitution of the United States?

The People

In 1787
The People, assembled in their own conventions, created and adopted the Constitution in their original capacity as private individuals, and not as agents representing States. The governments were passed by in silence and had no part in framing the original Constitution of the United States, and are properly not parties to it. The People in their private capacity as sovereigns created the original Constitution of the United States OR Government

In 1777
A federal government was created by the union of thirteen Colonies of Great Britain in “certain articles of confederation and perpetual union,” the first one of which declared that “the stile of this confederacy shall be the United States of America.” Each member of the confederacy was denominated a “state.” The confederacy, owing to well-known historical reasons, having proven a failure, a new Constitution was formed in 1787, by “The People of the United States” “for the United States of America,” as its preamble declares.

Therefore: The People created the Constitution for Federal and State Governments to adopt and ratify.

The convention of the People on September 17, 1789, resolved that the Constitution be laid before the United States in Congress assembled and afterword be submitted to a Convention of the Delegates of State governments for their assent and ratification. That as soon as the Conventions of nine State governments shall have ratified the Constitution; the resolution required the federal government to proceed without delay to execute their new Constitution.

The federal government adopted their new Constitution on March 4, 1789.
See: Article VII of Constitution of the United States
In convention Monday, September 17th, 1787
Congress of the United States, March 4, 1789