A specific item that is bundled in with related variants to form one distinguishable product is known as a product variant. Product variants have unique identifiers, such as price, and every variant is based on the same product definition.
Variants represents the same product with different features For example, the color of the product, Size of the product etc.
You can set the variants from the product catalogue in sellacious panel. When you create a new product, save it. save the product details in the product catalogue then after reopening the products you can see variant fields will be added to product, from there You can set and create variants for that product.