The Invoice Message field is used for displaying additional notes to the customer at the invoice level. Notes can be entered in the "Message" box towards the bottom of the invoice page as shown below:
When copy/pasting text from another source e.g. Website or Word/Pdf document, it is recommended that you right-click in the Message box and use the "Paste as plain text" option to avoid pasting any unwanted formatting or scripting code, as the box is a plain text field.
The Invoice Message appears on the invoice preview as shown below.
Default invoice message
A default Invoice Message can also be set up so that "new" sales records automatically default with the preset invoice message. The message can be overwriiten on the sales record at any time. To set up the default message, go to Setup > Preferences > Sales and enter a message in the "Invoice Message" box, then click Save Changes.