Retainage is a portion of the net bill amount that remains withheld or unpaid by the clients until they sign off on the work done for their projects. It reduces the overall amount due for the project. The clients pay the total or accumulated retainage amount later when either the project is completed or they have verified the quality and completeness of the project. You can apply the retainage from the Invoice Batch screen when creating an invoice. You can also set the percentage from the Projects screen under the Billing Options tab. It will be transferred automatically to the Invoice Batch screen when you create an invoice.