The amount received from the EU is a grant and not for providing a service to the EU, the coordinator or other partners. As such most State authorities will not require the issue of an invoice (as a grant). We suggest that there should be receipt for each amount received (even where the State authorities do not require this document - e.g. UK, but even there we suggest issuing a letter/form acknowledging receipt of the funds is a good idea). In theory, therefore, no invoice need ever be raised except if the State authorities require it or it is demanded by the EU and/or the coordinator, even after preparing the form C with details of costs etc. The local State regulations should determine when and whether an invoice is raised, but occasionally the coordinator and/or a PO in EU will demand an invoice.