Add or select an approved stock sale from the stock sale dashboard.
Click Create Approved Invoice or Create Draft Invoice to raise an invoice for the stock sale.
Doublecheck the invoice is correct - line item value, tax etc. You can do basic changes via Edit. However, generally if there is an issue with invoice line totals etc, Delete the draft and re-issue from the project or stock sale with corrections. Approve the draft invoice if that option was used. Note: The invoiceonly receives an invoice number once approved.
The stock sale will now list the relevant invoice number and can be dispatched if not already done so. By default, approved invoices are immediately queued to be sent to Xero. If you don't want this invoice to be sent to Xero (it may already be in Xero etc) click Skip Send to Accounting.