Before people can buy products in your Facebook Shop or Instagram Shopping account, you need to upload them in a Facebook Product Catalog. Product Catalogs are managed in Catalog Manager.
Products are created, updated and deleted using the following approaches:
The Product Feed should be provided in one of the supported formats (CSV, TSV, RSS XML, ATOM XML). You may already have a Product Catalog for Facebook Dynamic Ads, which can be extended with a set of mandatory fields specific for Commerce such as: inventory count, size/color variant, product category.