How can we manage ad hoc invoices (temporary) that aren't associated to a project and don't have time/expenses, say for training events or conferences?
BQE CORE is a project-centric software solution. So project is required for creating any sort of invoice. What you can do is create a project in this format: {Project}-Ad hoc for all such temporary or quick jobs. Then simply create a quick, manual invoice from the Invoices screen if it is not based on time and expenses. Check CORE Help Center for details.