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.
It is not known exactly when all of the horcruxes were made. The first horcrux, Tom Riddle's diary, was made in 1943 during Tom Riddle's fifth year at Hogwarts after he killed Myrtle with the basilisk. Marvolo Gaunt's ring was made into a horcrux later during Riddle's time at Hogwarts after he had killed his father. Voldemort accidentally made Harry Potter a horcrux in 1981 the first time he tried to kill him. Nagini the snake was made into a horcrux in 1994 after Wormtail had destored him to a living body.
He only made Seven.
one of the deathly hollows is a horcruxes
Harry didn't make Horcruxes, Voldemort did.
Harry destroys the horcruxes used the sword of Gryffindor.
Horcruxes are ficticious; there is no way you can live forever. The horcruxes in Harry Potter are made with a special spell. The spell is not mentioned (perhaps the author thought somebody would be stupid enough to try it out). It is done in combination with a murder. According to the Harry Potter story, that would leave part of your soul in an object of your choice.
it was made accidentally
No
Investigate about horcruxes.Investigate about horcruxes.Investigate about horcruxes.Investigate about horcruxes.
Horcruxes: Cup, locket, ring, diadem, harry, snake, diary. He dies when Harry finally kills alll of his horcruxes and Harry gets to kill him.
No, they are not.