The cabinet secretary is the successor of the secretariat of the Executive Council of viceroy. The efficiency of the cabinet depends to a large extent on the cabinet secretariat whose duty is to prepare in a meaningful way the agenda of the cabinet meeting, to provide information and material necessary for its deliberations, and to draw up records of the discussions and decisions both of the cabinet and its committee. It keeps the president, the vice president and all the ministers informed of the major activities of the government.
Prime Minister’s secretariat came in to being on 15 Aug 1947. Since June 1977 it is known as the PMO. It occupies the status of a department of the government of India under the allocation of Business Rule 1961 and has no attached subordinate officer under it. It is an extra constitutional institution that has no mention in the constitution.
The main task of it is to help the prime minister in the performance of his functions as the head of government. This office is not responsible for the prime minister functioning as head of the cabinet, but is responsible for his functioning as chairman of the planning commission. Owing to its function both the secretariat are important to run the country.