Thanks for getting back to us, @Tawni.

Allow me to provide additional details with the invoicing process in QuickBooks Online.

When emailing invoices in QuickBooks Online you'll have the option to set a default email message sent with sales forms. You can do this under your Accounts and Settings settings section.

Let me show you how:

1. Click on the Gear icon.
2. Select on Accounts and Settings.
3. Click on Sales.
4. Refer to the Messages section, from there you can enter your desired information that you wanted to see when emailing invoices to your customers.
5. Click on Save.

I've attached some screenshots to outline the steps. 

You can also visit these articles below about emailing sales transactions in QuickBooks Online for your reference:

• New improvements to invoice emails for QuickBooks Online.
• Customize invoices, estimates, and sales receipts in QuickBooks Online
• How to email or print multiple invoices and sales forms at one time.

This should guide you in processing your invoices in QuickBooks Online. 

Please know that the Community has your back should you need anything else. Have a great day!