But Harry does not know he is a wizard.
The Dursleys, as Muggle -- people without any magic -- as they come, do take Harry in, albeit grudgingly. They treat him like an unwanted pet, making him sleep in a cupboard, not giving him enough to eat and forcing him to wear Dudley Dursley's (their pest of a son) old clothes, making him work like a servant.
But just before Harry's eleventh birthday, a strange letter arrives for him, which perturbs Mr Dursley so much that he is in a fit. Harry doesn't get to read the letter, but they keep coming in all sorts of magical way till Mr Dursley packs the whole family off to a deserted island.
But at midnight, a giant of a man barges in and the truth is revealed. Harry Potter gets to know his identity, and is admitted to the Hogwarts school of witchcraft and wizardry, of which the brilliant and eccentric Professor Albus Dumbledore is the headmaster.