Create customTtransaction Body field that automatically displays the parent Customer record along with a custom Message

1. Navigate to Customization > Lists, Records & Fields > Transaction Body Fields > New.
2. Enter a Label.
3. Type = Text Area.
4. Un-check the Store Value check box.
5. Click the Applies To tab > Mark the Sale check box to apply the custom field the Estimate, Sales Order, and/or to the Invoice transaction form.
6. Click the Display tab > Select a subtab or main to display the field on the preferred location.
7. Click the Validation & Defaulting tab, mark the Formula check box and enter this SQL Expression in the Default Value field:

concat('For ordering information please contact ',{customer.parent})

8. Select the Save & Apply to Forms in the Save button.

Note: User may revise the message in the SQL expression and user may apply it to other custom field types and forms.