During the coding of an invoice in the Invoice Processing module, you can link a contract to an invoice line. It's also possible to link exported invoice lines from the Contract Management module to a contract.

To link invoice lines to a contract, follow these steps on the contract's view page, accessed by opening the contract using the magnifying glass icon.

At the bottom of the view page, under "Linked Invoice Lines," you can add new invoice lines by clicking the plus icon.

If there is a commitment linked to the contract (from the Commitments module), you can also link the invoice line to the commitment here.