Google recommends that you include the code on multiple pages, however, it makes it clear in the official docs that this is absolutely NOT required for the reCAPTCHA v3 system to work.
So if the article stated that websites were required to put the code on multiple pages (as the comment I replied to did) then the article is factually incorrect.
> To make this risk-score system work accurately, website administrators are supposed to embed reCaptcha v3 code on all of the pages of their website, not just on forms or log-in pages.