Hello there, @ken-amitigations.

I'm here to guide you on how to add the project name on your customer's invoice in QuickBooks Online.

You can add a custom field on your invoice template so you can enter the project name from there. This can be done in just a few clicks.

Here's how:

1. Go to Gear icon.
2. Select on Custom Form Styles.
3. Click on your invoice template.
4. Go to the Content section.
5. Click the Pencil icon on the upper section of the invoice template.
6. Select the Custom field in the lower section of the page.
7. Enter Project Name, then make sure the box is selected.
8. Click Done.

Once done, you can now create an invoice and manually add the Project Name details. You can also open an Invoice List report and customize it to view the Project Name.

Here's how:

1. Go to Reports and search for the Invoice List report.
2. Click Customize and select Filter.
3. Check the Project Name box and click Run report.

On the other hand, you may also consider adding the project name on the Description box or in the Message section of the invoice.

For more tips in customizing your sales templates together with emailing them, you can always use these links: 

• Learn how to personalize and add specific info to sales forms
• Email estimates, invoices, and sales receipts to customers

Let me know if you need more help customizing your sales forms in QuickBooks. I'm always around to help you.