Harry Potter | Harry Potter and the power of letters | Wizarding World https://www.harrypotter.com/features/the-power-of-letters-in-harry-potter
From Hogwarts book lists to Howlers, letters in the wizarding world hold a certain undeniable power, and no more so than for Harry Potter, the boy who never expected to be written to at all…
For Harry, the letter is also the first link between him and his parents.