Who gets bit by a werewolf at the end of Harry Potter and Deathly Hallows?

There is no werewolf bite at the end of Harry Potter and the Deathly Hallows.

You might be thinking of the scene where Remus Lupin is bitten by Fenrir Greyback in the third book, Harry Potter and the Prisoner of Azkaban. This is what ultimately leads to Remus becoming a werewolf.