how to add CITB to an invoice

Hi Rosse, thanks for posting on the Community 

QuickBooks Online doesn't support CITB. If the tax is related to the Construction Industry Scheme (CIS), you can use the CIS rate in QuickBooks to deduct from the invoice total (CIS Suffered). 

If the charge does not relate to CIS, we'd recommend speaking with your bookkeeper or accountant for the best way to record this in QuickBooks. If you don't already have an accountant, you can find a QuickBooks Certified ProAdvisor near you on our online directory.