Harry didn't make Horcruxes, Voldemort did.
Destroy the horcruxes
Harry told him about Voldemort's using his blood to create a new body.
Horcruxes.
No.
Voldemort otherwise known as Tom Riddle
voldemort has a couple horcruxes in harry potter. when you kill a person your soul splits. when your soul splits you can hide that part of the soul in an object. voldemort had 7 horcruxes. when all the horcruxes are destroyed, voldemort dies. [hint, hint if you haven' t read the 7th book]
He wanted to become immortal.
Lord Voldemort had seven Horcruxes;The diary.Marvolo Gaunt's ring.Salazar Slytherin's locket.Helga Hufflepuff's cup.Rowena Ravenclaw's diadem.Harry Potter.Nagini.He also had part of his soul inside him.
Inside Marvolo Gaunt's ring, one of Voldemort's Horcruxes (although Voldemort was unaware of it).
They had to destroy seven horcruxes. Voldemort wanted to divide his soul into seven pieces; since he himself had one of the seven pieces, that would have required only six horcruxes. However, he accidentally created one more horcrux.
Singular horcrux, plural horcruxes.