Trifold book box like this
Label varies but the last 5 have been just fakku, its po box, city and your address, tracking number ect ect. Some times its the store name or the owners dog's name or the owners. Nothing seem like it tells people there's Chinese cartoons doing it inside.
I only have done doujinshi, singles and one time a double order so pass that I'm sure it's a plain box or similar.