To add a billing contact for a project, follow these steps:

1. Go to the Projects screen and click on the project for which you want to add the billing contact.
2. On the General > Details tab, under Billing Contact, select the client contact from the drop-down list that you want to set as the billing contact for the project.
3. You must check the Send Invoices to Contact option if you want Core to send the project invoices and statements to this specific contact.

Note: You need to have the billing contact as a client contact in the Clients > Details > Contacts screen before it shows up in the drop-down list here. Check the Core Help for details on that.