To create a SKU for a product in Ecwid:
Click on Catalog > Products > New Product
The SKU is a required field. When you click on save a sequential SKU number is applied.
Note: Ecwid distinguishes between real and virtual products. To indicate that a product needs to be sent to the fulfillment center, it is necessary to specify a weight for the product. Otherwise, Ecwid treats the product as virtual.