This message comes from the payment terms you set and can be changed on the projects. To do so:
- Open the Projects screen from the side menu > Projects.
- Select a project from the grid and view its details.
- Under Settings > Billing Options, set the Terms to the desired setting. You can select one of the terms provided, such as Net 30, or create your own term.
- Click Save. The new payment term is reflected on invoices moving forward and it does not display the Due Upon Receipt message on invoices anymore.