Those product attributes are called "Custom Field" and they are created through Virtuemart Backend.
The custom field you see in the "Product 02" (in our DEMO) is called: Cart Variant Custom Field, there are several types as well.
Watch this video tutorial below to learn how to add custom field in Virtuemart 2.0.xx
I just found this youtube video for you by looking at google.com, do some further research if you would like to have deeper understanding. (There are many article/videos about custom fields)