RE: How do I move a file in SharePoint/OneDrive to a folder in the same SharePoint/OneDrive account? I'm on a Mac.

Hi Sara,

You can try the OneDrive for Business Mac sync client to achieve your goal. For details, please refer to the following blog:
http://blogs.office.com/2015/01/28/onedrive-business-comes-mac-ios-devices/

If you have any question, please feel free to let me know.

Thanks,
Kevin Huang