Elections for the post of first President of India were to be held on 24 January 1950. There was only one nominee for the post, Rajendra Prasad and he was elected, unopposed, as the President.
The Constituent Assembly of India met for the last time on 24 January 1950, two days before the Constitution came into effect on the 26th. On that day, they declared that the song Jana Gana Mana was the National Anthem of India, signed a Hindi copy of the constitution and voted in a new President. Prasad had been the president of the Constituent Assembly from December 1946. He was proposed to be the first Indian president by Jawaharlal Nehru and was seconded by Vallabhbhai Patel. There were no other nominations and hence the secretary of the assembly, H. V. R. Iengar declared that Rajendra Prasad was considered to be duly elected to the office of President of India.
He was sworn in on the first Republic Day, 26 January 1950, by the Governor-General of India, C. Rajagopalachari, in the presence of the Chief Justice of India, Harilal Jekisundas Kania. Prasad's sister, Bhagwati Devi, had died the previous day, 25 January. He attended her cremation after the founding and swearing-in ceremony.
I have to inform honourable Members that only one nomination paper has been received for the office of the President of India. The name of that candidate is Dr. Rajendra Prasad. ... His nomination has been proposed by Pandit Jawaharlal Nehru ... and seconded by Sardar Vallabhbhai Patel ... I hereby declare Dr. Rajendra Prasad to be duly elected to the Office of President of India
.. the oath of office was taken by Dr. Rajendra Prasad, the President-elect of India, in the presence of the Chief Justice of India, as prescribed by the Constitution.
After his sister died on January 25, 1950, a day ahead of the historic moment when the Indian Constitution was going to come into force, Dr Rajendra Prasad attended the cremation only after the founding ceremony of the Republic of India.