Image drop shadow can be easily created by using Photoshop filters. But it is not possible to create a 3D shape of product by applying it. By using drop shadow, a fake shadow can be created on the rear side of product, which can be set at various angles such as left, right, top, bottom and shadow opacity, the glow can be created. But it is cheaper than natural or product shadow.
Generally it is applied to some specific products, such as clothing items (shirt, T-shirt pant, panty, underwear, etc.), product item (book, table clothes, pen, mobile, wallet, flat, simple ring, flat chain, ear ring etc.)