Hi Dave264. Thank you for posting on the Community. The CIS reverse charge does not appear on the invoice itself; however, it will be reflected in Box 6 of your VAT return.
In QuickBooks Online (QBO), be sure to select 20.0% RC CIS (Reverse Charge for CIS), as this is the correct VAT code for accurate processing. It's important to avoid using 20.0% RC SG or 20.0% RC MPC, as these represent different types of reverse charges and are not applicable in this situation.
For clarity, I've included a screenshot below that illustrates the proper use of the 20.0% RC CIS VAT code.

I also recommend reviewing the article Understanding VAT Codes in QuickBooks, which provides valuable insight into commonly used codes and explains how to correctly apply them to your sales and purchase transactions in QBO.
Feel free to return to this thread if you have any further questions about VAT codes or need assistance with anything else in QuickBooks. I’m here to help.