How do I add a deduction to an invoice

Thanks for sharing your concern in the QuickBooks Community, @m-b-burston-gmai.

The option to add a deduction to an invoice is unavailable in QuickBooks Self-Employed (QBSE). For now, you can manually enter the exact amount of the invoice before sending it to your customer. 

I can see how this option would be helpful for you and your business. Therefore, let me take note of this as a suggestion to improve your QuickBooks experience.

In the meantime, I recommend visiting our Firm of the Future site. This is where we share recent happenings and future developments, such as updates to newly added features.

Should you have any follow-up questions or concerns, don't hesitate to post again here in the Community or leave a comment on this thread. Take care and have a good one.