Converting roles are those that have the ability to convert players to their own team. These roles are enemies of the Village (excluding the Cupid), and must be killed for a Village win.
To win as a converting role, all players must be converted (Every villager (except Cursed) and solo voting roles). That means that eliminating all Werewolves is a requirement. The only exception is Cupid, whose couple just has to be alive until the very end.