GST rate which is charged for that service and goods shall be shown separately in the invoice if rates are different otherwise you can show in a single entry. for example if you bill rs 10000 services chargeable @ 18% and rs 10000 goods chargeable @ 5% then you must show gst @ 18% on 10000 (i.e.1800) and gst @ 5% on 10000 (i.e. 500) separately in the same invoice. In case both are chargeable at 18%, you can simply show gst @ 18% on 20000 (i.e. 3600) in single entry.