Submitting images to adobe stock

You may use anything you want to create. But all what you submit needs to be cleared by property releases. So, if you use a model created by a third party, and you put it into a scene to render, you need to have the right to use that model for commercial applications. If you model a character after a living person, you must have a model release, etc. Your renders will be considered more or less like photographs.

This is also true for sharpness, exposure, noise…

So be sure to read the manual before starting very complex renderings of objects that will never pass. If you are new to stock, you should consider these resources: https://helpx.adobe.com/stock/contributor/tutorials.html
Please read the contributor user manual for more information on Adobe stock contributions: https://helpx.adobe.com/stock/contributor/user-guide.html
See here for rejection reasons: https://helpx.adobe.com/stock/contributor/help/reasons-for-content-rejection.html
and especially quality and technical issues: https://helpx.adobe.com/stock/contributor/help/quality-and-technical-issues.html