I'll help with your question about invoices, annieb2.
For now, we're unable to create an invoice without providing an email address in QuickBooks Self-Employed. This particular section of the program is mainly used to invoice customer and collect payments from them.
You'll want to enter your own email address so you can proceed and save the transaction in your account. Check out these articles about tracking and sending invoices in QBSE:
We'll forward a feature request about being able to create an invoice without typing in an email. Our engineers are constantly collecting feedback and review them for future updates.
Don't hesitate to visit us again if you need more help adding invoices and categorising transactions.