There is no way to enable Shift+Enter evaluation of cells for published views accessed by users who do not have a Wolfram Cloud product. When a user follows a published link (which use the www subdomain) he or she is given the option to open the notebook in his or her preferred cloud product using the Open In menu in the page footer. If this user opens the published notebook in a product view, e.g. Wolfram|One, he or she would be using his or her own account to interact with the notebook and would not be using your cloud credits. You probably don't want that user changing the notebook even if you do want them to be able to do Shit+Enter evaluation. If you set the {{AutoCopy}} option on the notebook to {{True}} but leave the notebook read only then the user will be prompted to make his or her own copy which can be changed without affecting the original. You can use
SetOptions[co, AutoCopy->True]
to do that. Alternatively, you can set the notebook permissions to All -> {"Read", "Interact", "Edit", "Evaluate"} (the Execute permission is for API's and not notebooks), so that the user can evaluate and make changes to the notebook but nothing they do will be saved. That's what we do with some of our sample content like the "Things to Try" notebooks we publish.
