When creating any invoice in ABOSS, the default for the due date is set on 14 days.
You can find this at the bottom of your invoice-settings:
You can change the due date in two ways:
Change 'Payment due in days' to another number of days - you will see the 'Payment due date' will also change.
Change 'Payment due date' to another date - you will see the 'Payment due in days' will also change.
These number of days/ this date will now be used on your invoice.