Greetings, @MB505!
Let me share a few options on how to add memo in your sales receipt.
To start, you have the option to change the title column of the sales receipt by creating a customized form.
Here's how:
- Go to the Gear icon.
- Under Your Company, select Custom Form Styles.
- Click New style.
- Choose Sales receipt.
- On the Content tab, click EDIT LABELS AND WIDTHS.
- Type in Memo in the box beside Description.
- Click on Done.
Then, you'll have to select the newly customized form when creating a sales receipt by clicking Customize at the bottom of the page.
You can also add a memo field on the sales receipt.
Let me show you how:
- Go to the Gear icon.
- Under Your Company, choose Account and Settings.
- Select Sales, then go to Sales form content.
- Enter Memo on the dialogue box beneath Custom fields.
- Select Save and then Done.
Now, if you are referring to a message for a customer you can type it in the Message displayed on invoice or Message displayed on statement.
Here's a screenshot for your visual reference.

Feel free to read these articles to learn more about those options:
Please know that you can always get back to us by leaving a comment below if you have any other questions.