An offer consists of the products that you are offering for sale to your customers and it includes all product-related and price-related information. You have the possibility to update your offer at any time. The difference between the product portfolio (product catalog) and an offer is that the products from your product portfolio are not visible to anyone but you, but they can be used to create offers for your customers. You can upload your product catalog and then select from it the products that you want to offer to your customers and you can also change the price for your products when you create an offer.