[dasickis]

Generally we call inserts: marketing messages companies put in each shipment.

There's another material called dunnage i.e. fill that is placed such as air packs, bubble wrap, paper, cardboard, mushroom (yes a product made from mushrooms!), etc. are used to keep the product tight.

Another method is to use a smaller box which cuts down on both shipping costs as well as is a more secure way of securing products.