Variations, Grouped Product URL

Hi, im wondering if someone can. Ive noticed lots of woocommerce sites that have “options” on a product, When the product is selected from the dropdown the URL changes the product options url. If this done with a plugin? We have lots of items and it would be much easier to import them as simple items and link them together with a grouped item. Here is an example. When you change the size of the item you will notice the URL changes as if its a single item that its displaying? Many thanks. https://tinyurl.com/wq8p6ps