It’s great to see you in the Intuit Community, welcome.
Let me point you in the right direction about categorising your invoice.
QuickBooks Self-Employed is used for tracking business income and expenses to estimate the taxes. To help guide you categorise the transaction, you can refer to the About SA103F Categories article for detailed information.
From there, you can select which category to use to track the invoice. I'd recommend consulting with your accountant to make sure the chosen categorisation is the best fit.
This should point you in the right direction. If you have additional questions about QBSE, leave me a comment below. I'll be sure to get back to you.