How can I show Signle Attribute in Shop/ Archive Page? #
To enable single attribute navigate to WordPress admin menu WooCommerce => Settings => Product Swatches=> Archive/ Shop
Then see Special Attributes

Special Attribute #
First check Show single attribute on archive page then select the attribute and set display event lie on click or on hover.
Attribute display limit if set a number here like 3 then if a product has then then 3 attributes then it will show more link.