Create a Commerce Catalog
The catalog is the highest level of organization for categories. Before you can create any categories for a site, you must first create a catalog to assign the categories to. Each website can have only one catalog. To access Commerce catalogs, go to Commerce > Content Management > Catalog & Categories > Commerce Catalogs. See Set Up Commerce Catalog.
Note:
If you attempt to create a category and no catalog yet exists for the site, a new default catalog is automatically created for you.