The preamble of the constitution of India, Declares India a Sovereign Socialist Secular Democratic Republic.
Unlike England where a hereditary monarch, either a Queen or a king is the head of the State, India has an elected President as head of the State with a fixed tenure of office.
The President is the supreme head of all the constitutional wings of the State, i.e the legislature. Executive, Judiciary and Armed Forces.
The President supervises their functions and ensures adherence to constitutional provisions by theses bodies.
The President represents the entire nation and upholds the constitution in every sphere of State’s activity.
But unlike the President of the USA, where the President of the republic wields de-facto (real, functional) executive powers, the President of Indian Republic is not vested with direct executive responsibilities.
Such direct and real executive responsibilities are assigned by the Constitution to a Council of Ministers led by the Prime Minister, and such Council of Ministers, both collectively and individually responsible and accountable to the union legislature.
Thus, our Republican form of State is different from American form of Republic, where it is Presidential executive.