Add a Product offers the option to create variations, using a web-based interface. See About parent-child relationships to understand how product variations work on Amazon.
Before you list a product variation, check whether the variation of the product exists in the Amazon catalog. To do this, click on Add a Product under Inventory drop-down, and search for the product variation you wish to sell. Results are more accurate if you search with product identifiers (UPC, EAN, JAN, or ISBN). Based on the search results, following are the two ways you can use to Add a Product to create variations: