Symphony Desktop can be used with your iPhone or iPad, as shown in the manual on this page.
iPad Pro with USB-C: You can use a direct USB-C to USB-C cable.
Lightning port iOS devices: You must use the Apple USB-C to USB camera adapter and a USB-C to USB-A cable. The cable is included with the Symphony Desktop. The adapter is available from Apple, as shown here.
NOTE – The Symphony will NOT connect to a Lightning iOS device using the Apple Lightning to USB-C charge/sync cable shipped with newer Apple iOS devices. The camera adapter is needed to allow the iPhone to recognize Symphony Desktop properly.