You should indicate only the -document number shown on the invoice. It is comprised of 8 digits starting with a “9”. It is very important to use the correct reference - if you do not provide the document number or a payment advice - EASA will be obliged to return the payment to you, at your expense.
Please remember that EASA does not accept cash, cheques and credit card payments nor payments in currencies other than Euro. Only wire transfers in EURO are acceptable means of payment.