Marketplace refers to a wider concept than online sales. On this platform, different companies or stores can advertise and sell their products, thus offering a wide range of options to the client.
It allows you to buy products from several different stores and make a single payment, instead of going through multiple payment processes on several websites.
At the same time, for companies it is synonymous with collaboration. By advertising their products on a Marketplace, companies - whether large or small - gain more visibility and increase sales.