For each customer or organization, go to Sales/Organizations/General to assign a credit limit. You can choose the amount freely.
All open orders are counted towards the limit. Orders that have already been invoiced are not included, because Keyline cannot know whether an invoice has since been paid.
When the limit is reached, a red warning message appears. You can still send the order to production.
This means all orders currently in production are added together. Once the invoice is issued, the amount is deducted. Keyline is not accounting software, so it cannot post incoming invoices or handle dunning.