The President of India has to perform the following functions:
Legislative Powers: He summons and prorogues the sessions of the two Houses of Parliament and can dissolve the Loksabha before the expiry of its term of five years. A bill passed by the Parliament must receive his assent before it can become an Act. He can withhold his assent from any Bill other than a Money Bill. But if it is passed by the Parliament for the second time, the President is bound to give his assent to it. He can promulgate ordinances at any time when the Parliament is not in session but they must be ratified by the Parliament when it reassembles.
Executive Powers: The President is the supreme executive head of the state. He hold the supreme command of India's defence forces and has the powers of declaring war and peace. All important appointments are made by the President. He appoints Governors of the state, Ambassadors and other diplomatic representatives, the judges of the Supreme Court and High Courts, Attorney-General, the Chairman and the Members of the Union Public Service Commission and members of various Commissions like Election Commission, etc. He also makes the appointment of Prime Minister and on his advice other Ministers of the Union Government. The administration of the Union Territories is run by Chief Commissioners or Lieutenant Governors on behalf of the President who appoints them.
Financial Powers: No Money Bill and particularly a bill imposing or waiving a tax or duty which affects the states can be introduced in Parliament without the recommendation of the President. He can appoint Finance Commission to make recommendations on the Union-State financial relations and financial matters generally and take actions on those recommendations.
Judicial Powers: He has the powers to grant pardons, reprieves or remission of punishment or to suspend, remit or commute the sentence of persons convicted of any offence.
Emergency Powers: Though the President is not very powerful as far as his normal powers are concerned, in cases of emergency he enjoys enormous powers. The Constitution provides for three kinds of emergencies, proclamations for which have to be issued by the President as and when necessary. These are (i) external aggression or internal disturbance threatening the security of the country; (ii) failure of constitution Machinery in the State; and (iii) financial emergency.
Discretionary Powers: The President is not a mere rubber stamp, as is generally presumed. He con exercise his discretion to return a bill for reconsideration as President Zail Singh did in case of Postal Bill and President K.R. Naraynan's recent stand in respect of imposition of President Rule in Uttar Pradesh.