Product variation allows you to create multiple variants of a product. 

For example, variation attribute “Size” of a product can have the values – S, M, L, and XL.

Follow the steps to manage product variation:

Select the category of the product you want to add product variation.

Add new product field and rename it “Size” and click on “Product Variation” field and click on "Save" button.

Now, select “Custom Forms” from the left side menu and click on “Pick List” to create a new list and rename the field “Size”.

On the right side of the page, add new values – S, M, L, XL and Click on "Save" button to save the changes