What are due days?

Due days refers to the number of days after the document date (i.e., invoice date, voucher date) when payment is considered overdue. For example, if the invoice date is May 10 and the due days = 10, then payment would be due 10 days later, on May 20. For proximo terms, the due days refers to the day of the month when payment is due—that is, due days = 10 means due on the 10th day of the month.