The Utrecht Summer School does not directly send invoices or any other documents to paying institutions. You can, however, change the address and add relevant details (such as VAT nr.) on your invoice to show the institution that is making the payment.
When you click on ‘my courses’ in your personal account, you can select 'generate invoice'. It leads you to a page where you can change the invoice address to the address of your institution and add the necessary details. Afterwards, you can download the invoice and send it to the relevant party.