Invoice

You can use the Custom Form Styles feature to add a message to your customer, Neil. Let's go over some details to help you achieve this task in QuickBooks Online.

Customising the appearance and layout of sales forms is a simple yet effective way to enhance your business communications. The steps are slightly different for different editions of QuickBooks Online. The processes below are applicable for QBO Essentials, Plus, or Advanced: 

1. Go to the Gear icon and select Custom from styles.
2. Look for the standard template you use and click Edit.
3. From there, choose the Content tab.
4. Select the footer on the form to start editing that section.
5. You can place the text from the box under "Message to customer on". Please know that the message you entered here applies to all sales forms, except estimates. 
   
   
    
6. You can also utilise the "Add payment details and footer" box. It's all up to you.
7. Click Done to save changes.

For more details, check out this article: Customise invoices, estimates, and sales receipts in QuickBooks Online. This also includes the steps in case you want to customise a specific form.

In case you want to create templates for recurring transactions, see this link for future reference: Create recurring transactions in QuickBooks Online.

Let me know if you need further assistance with the customization process. I’ll get back to help and make sure this is taken care of for you. Have a good one!