A buyer persona (aka. user persona, customer persona) is an avatar that represents the aggregate of your target customers. The persona answers the questions: Who is my ideal customer? What do they want, in life, at work, at home? What do they need? What are they trying to accomplish? What goals drive their behavior? What are they looking for that I can provide?
These are the million-dollar questions for any business, because without these answers, you won’t achieve product-market fit.
For e-commerce businesses especially, having a thoroughly fleshed out buyer persona is vitally important, because it’s not enough to only understand what your customer needs and wants on the surface, you need to understand their entire psychology to create and sell your products effectively.