Add two amounts of coins

I have two coins with the same puzzle_hash , I would like to spent these amounts in a third coin with the addition of the amounts of the first coin and second coin.

Is it possible? how could I add these amounts in a single coin ?

Yes this is certainly possible. All that matters in a spend bundle is that the sum of the outputs is <= the sum of the inputs. You can spend one and output NO CREATE_COIN conditions, and spend the other one creating a coin that is the sum of the two inputs.