How to choose and create virtual product variations in Shopify?

[RobertF]

Hi,

I am looking to do something very similar to this page that is build with Shopify. I would love to know which app is used for choosing the variations/creating the final product to be put into the cart.

https://www.sterntaufe-deutschland.de/products/sternbild-sterntaufe

I really appreciate any lead.