Invoice lines are automatically generated by timesheets or created manually.
This page describes how to let timesheets automatically to convert to a invoice line.
Click 'Financial' | 'Invoice lines'
Click 'Create invoice lines'
Select the desired timesheets
The timesheet needs to be approved, otherwise the timesheet isn't invoiceable.
Timesheets that cannot be invoiced yet because the invoicing period isn't complete get the status "Invoicing".
These will be turned into invoice lines only after the invoicing period is complete
Timesheets for a fee that cannot be invoiced get the status "Not invoicable". No invoice line will be created.
The menu item "Invoices" offers "Create invoices" which starts as above and has a second step to create convert invoice lines to invoices.