Sign Board
From Nookipedia, the Animal Crossing wiki
Sign Boards are items in Animal Crossing; they can be bought from Nookway or higher for 200 bells. Players can drop them. Once it is dropped, players can walk to it and press the "A" Button. Then, they can copy their designs on it. Signs can be removed with the "B" button. Players cannot place them on the Island or in other players' towns. Players may change them, however.