What are attributes, and why do I need them for variants?

An attribute is a reusable set of options, such as a "Colour" attribute with the values Red, Blue and Black, or a "Size" attribute with S, M and L.

You create each attribute once, then use it on any Variable product. The product's variants are the combinations of those values (for example Size M / Blue), and each variant has its own price, stock and image.

Because attributes are reusable, every T-shirt can share the same Size and Colour lists instead of retyping them per product.