The header and footer that can be configured by default appear above the items on the invoice for the header and below for the footer.

1. Click on the Customization module
2. Click on Finance
3. Click on Settings
4. Click on Report: Header/Footer
5. Click on Edit Header/Footer
6. Enter the desired text (header and/or footer)
7. Click on Save

The text appears on the invoice.

Note: It is possible to add/remove/modify the header and/or footer for a single invoice. When you are viewing your invoice, click on Modify header and footer; the change will only apply to the current invoice.