Qlik Sense Desktop is our free product, licensed for individual business and personal use. It does not have section access (dynamic data reduction) security built into it. Yes you are correct, Qlik Sense Server does have this capability. I assume you mean bu access level, data level / row or column level security? If so, this can be done only with Qlik Sense Server. Again - Qlik Sense Desktop is only intended for individual users, so applying section access to locally created Qlik Sense apps - really would not make much sense etc.
Hope this helps.