It is used:
When the first word of every new sentence and of every new line of poetry should begin with a Capital Letter -►- Ram is going to Bombay. He has to buy a car.
The Pronoun I and the Interjection ‘Oh’ and ‘O’ are always written with a Capital -►- My sister and I will return soon.
The first letter of a Proper Noun or a Proper Adjective is always a capital -►- Rahul, Tarun, Delhi, Bombay, etc.
All Nouns and Pronouns, which indicate the Deity (god) are written with a Capital Letter -►- God, the Almighty, the Lord.
The capital letter is used to begin Direct Narration in a sentence -►- He said, “Man is Mortal.”
Example:
This part actually belongs to the new model Hero Honda,” said Harjinder Singh, the chief mechanic at Bright Automobiles.
Satisfied by Sonal’s explanation, the Principal remitted her fine.
The speaker said, " We are planning to build a school here.
The Impact of Television on Children.
Anu Mehta is my close friend.