2C is an artificial and forcing opening showing a powerful hand that is forcing to game.

The responses are:

2D 7+ points

2H 0-6 points

2S 5 card or longer spade suit

2NT 5 card or longer heart suit

3C natural

3D natural

3H 0-2 points, balanced hand

3S 6 card spade suit headed by three honors

3NT 6 card spade suit headed by three honors

4H solid six or seven card suit

4S solid six or seven card suit