Hi @Soho1, 

What @Regina_Lend_A_Hand_Accounting discussed about the messages is correct. The default messages for each sales form are unique. The Message displayed on invoice field that you see on both invoice and estimate page will only display on invoice and not on any of the other sales forms.

There’s also an option for you to personalize your messages for each sales form. Please check this article for further details: How to Set Up or Change Customer Messages.

If there’s anything I can help, feel free to post again. Have a great day!