This article is not great. It doesn't link to anything other than itself and two of those links are "donate" and "subscribe".
I found this Apple Insider page with more information and an actual description of how it works, from someone doing journalism instead of soliciting donations and subscriptions: https://appleinsider.com/articles/26/02/25/how-age-verificat...
It's going to take some more searching to find an article that shows what age verification looks like for newer Apple accounts. According to that article if you have a long-standing Apple account and/or a credit card in your name in Apple Pay it might be enough to confirm you as 18+.
>According to that article if you have a long-standing Apple account ...
I can confirm that is the case.
It links to fca.org, gov.uk, and racfonudation.org. I think the goal of this page is activism rather than journalism though, and the donation links are a much more apt way for privacy activism funding than ads like on that news site.