The purpose of the Preamble is to clarify
1. who has made the Constitution,
2. what is the ultimate sanction behind it,
3. what are its goals and objectives,
4. what is its source (and)
5. what is the nature of the polity which is sought to be established by the Constitution.
Actually, the preamble is the opening statement to the United States Constitution.
The words in the Preamble ::
'We the people of India, in our Constituent Assembly, do hereby adopt, enact and give to ourselves this Constitution'.