● The Preamble is called the introduction letter of the Indian Constitution. ● The preamble can be referred to as the preface which highlights the entire Constitution. ● It was adopted on 26 November 1949 by the Constituent Assembly and came into effect on 26 January 1950 , celebrated as the Republic day in India. ● The preamble was made in 1947 but adopted in 1949. ● The preamble was amended by the 42nd Constitutional Amendment Act in 1976 , in which three new words Socialist, Secular, and Integrity were added.