"How to send an invoice and add a line which subtracts 20% cis"

Hi, usert-ruddick.

 As of now, the CIS feature is only offered in our Small Business products. We're unable to use this for Self-Employed transactions. If you'll want to have this feature, you may consider subscribing to QuickBooks Online (QBO).

To know more about our QBO products and their offered features, I suggest checking our pricing guide https://quickbooks.intuit.com/uk/pricing/. 

Additionally, I encourage visiting these articles to learn more about how to manage CIS transactions:

• CIS in QuickBooks 
• Already using CIS in QuickBooks?

The Community team will continue helping if you have other concerns or questions. We're just a few clicks away.