Used to ask questions regarding identity or person involved.

कौन

English Usage: "Who made this beautiful painting?"

Hindi Usage: "यह सुंदर पेंटिंग किसने बनाई?"

A pronoun used to refer to a person or people.

कौन

English Usage: "Who is coming to the party?"

Hindi Usage: "पार्टी में कौन आ रहा है?"

Used to introduce a clause that gives more information about a person.

जो

English Usage: "She is the one who won the award."

Hindi Usage: "वह वह है जो पुरस्कार जीती।"