The Constitution is divided into three main parts:
1) The Preamble outlines the six main goals of the Constitution which are to form a more perfect Union, establish justice, ensure domestic tranquility, provide for the common defense, promote the general welfare, and secure the blessings of liberty.
2) The Articles establish the framework of the U.S. government and are divided into seven sections.
3) The Amendments, of which there have been 27, with the first ten known as the Bill of Rights added in 1791 to formally change the Constitution over its 200+ year history.