Using iTunes gift card on the web?

I am using my iPhone 15 running iOS 18.3.2 and I just received $50 on an iTunes gift card.

I want to buy items on store(dot)supercell(dot)com using my gift card because they have bundles on the website that the Clash of Clans in-game shop does not have.

How can I purchase the items I need, with my iTunes gift card?