If you create a new app from a template, like service desk as an example, the app automatically creates an Excel file on OneDrive to be used as a data source. I haven't been able to figure out how it does that and I can't see any controls in the PowerApp that would do that. Can someone please tell me how this is done, it is driving me bonkers
This is not currently supported in the powerapps creation experience, it is a scenario for those templates using them from the powerapps site only. As far as I know, this isn't a high prioerity item for us to pursue right now - but if this is an important scenario for you, please submit an idea on the Ideas board for voting so we can look into it accordingly.