Billing Docs: add SEPA transfer character limit warning to payment details section

Author: Raluca Bahri

articles/cost-management-billing/understand/pay-bill.md

@@ -126,6 +126,9 @@ Alternatively, if your invoice is under the threshold amount for your currency,
 >[!NOTE]
 > When multiple invoices are remitted in a single wire transfer, you must specify the invoice numbers for all of the invoices.
 
+>[!IMPORTANT]
+SEPA (Single Euro Payments Area) transfers allow up to 140 characters in the payment details field. Exceeding this limit may cause processing issues.
+
 ### Bank details used to send wire transfer payments
 <a name="wire-bank-details"></a>