Use permission (free assets)

The free assets can be used for commercial and non-commercial applications according to the licensing terms. Depending on the asset type, a free aset comes with a standard license (photos, illustrations) or an enhanced license (videos, ...). See here for more information: https://helpx.adobe.com/stock/faq.html. Jump to the free collection. 

As EBQ said, Adobe employees won.'t give you more information than what is found on the Adobe website. In my view that information is clear and precise and easy to understand for most applications. 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).

As representatives of Adobe my colleagues and I cannot comment on licensing. There are links provided on this forum for licensing terms if you cannot find what you need you may need to consult an attorney.