What is an offer?
Whenever a product or a variation is created on your Seller Portal, they are automatically sent to the Marketplace. However, it does not mean that this product is ready to be displayed in the marketplace window and sold. You need to set price and stock conditions for it to become available for sale.
Offer is the name we give to a product or a seller variation sent to the marketplace and that had its price and inventory configured. When you set price and inventory conditions, you make your product or variation ready to become an offer.
What is the difference between an Offer and a Product?
Products are your store items, which are added to your catalog, but are not available yet in the marketplace window. A product will only become an offer when price and inventory conditions are set.
Offers are your store products that had their price and inventory already configured and were activated on the marketplace.
In the illustration we can see a series of offers from a seller in a marketplace window with the product variations.

How do I know if my product was sent to the Marketplace?
After setting the price and inventory for your product, the offer will be automatically created in the marketplace.
In the Shared Products dashboard, the 'Status' column demonstrates if the product is available or not in the marketplace. Products that are "Active" already have offers created in the marketplace. Products that are "Inactive" have not yet been sent to the marketplace. To send them, follow the instructions in the Product Details article.