The short answer is that a product description is exactly that – a description of the product, including its key features, benefits, and specifications. Beyond that, though, it is a guide for your potential customer to better understand your product, gauge whether it answers their needs, and decide to purchase it or not.
A product description for a face cream, for example, might say what ingredients it’s formulated with, what skin concerns it helps to tackle, and which skin type can benefit from using it. Then, the customer can assess whether it is right for their skin concerns and type, with all the relevant information they need to make that decision at their fingertips.