"Where do you live" is correct.

My name is Vivek.

I'm just sitting.

yes, this is true.

A word or group of words that expresses an action, an event or a state.

A vocabulary is a set of familiar words within a person's language . A vocabulary, usually developed with age, serves as a useful and fundamental tool for communication and acquiring knowledge. Acquiring an extensive vocabulary is one of the largest challenges in learning a second language.

Who is your best singer? --- Correct.

"I speak English." is correct.

Hi my name is Vivek.

Hi! Welcome. You can learn English by taking lessons, practising and completing daily homework as well.