Source reference AI-generated image

You do not need to credit stock assets for an advert. You only need to credit assets for editorial use, and when you credit other assets.

How to credit can be checked in the licensing instruction/terms.

Look here for more information on licensing: https://community.adobe.com/t5/stock/links-for-licensing-terms/td-p/11366788
(Disclaimer: As always with licensing, this is my interpretation of the rules. I think they are correct and advice is based on reading and interpreting the licence terms and on fair use for both the buyer and the artist/stock company, but I cannot rule out that my interpretation is wrong. I'm not an Adobe employee).