Soup-style is the default preparation for instant noodles — noodles cooked in boiling water or broth, then served in that liquid with seasoning. This is the format Momofuku Ando invented in 1958 with Nissin Chikin Ramen, and it still accounts for the vast majority of instant-noodle products sold worldwide. Japanese shoyu, shio, miso, and tonkotsu ramen are all soup-style, as are Korean ramyeon, Thai tom yum, Vietnamese pho, Chinese beef noodle, and Singapore laksa instant variants.
In practice, soup ramen is prepared by boiling 400-500ml of water, cooking the noodles for 2-4 minutes, and either adding the seasoning directly to the pot or pouring the noodles and liquid over the seasoning in a bowl. Premium soup ramen often includes a separate oil sachet (kotteri / aroma oil) added after cooking rather than during, to preserve the lipid-soluble flavour compounds that would otherwise volatilise in boiling water.
Compared to dry or stir-fry preparations, soup-style demands more from the broth: with no sauce to carry flavour, the seasoning powder, oil, and any retort-pouch inclusions are the entire character of the dish.