How to create custom attribute for configurable product in Magento 2
Login in to Magento Admin
Go to Stores – Attributes – Product
Click on “Add New Attribute”
Fill up attribute details choose attribute types and add values of attribute
Don’t forget to select proper attribute scope
In the storefront properties select properties according your needs. There are have many options.
For creating configurable product please visit our post How to create configurable product.
Note : Select this created attribute for configurable product.
After following all steps finally you find your product on assigned category page.