Hi there, Barry.

Welcome to QuickBooks Community. In QuickBooks Online (QBO), you can create multiple invoice templates using Custom form styles, but only one can be used at a time. You can set a default template or manually select a different one for each invoice.

Here's how to create different templates:

1. Navigate to the Gear Icon and choose Custom form styles.
2. Click the New style button in the top-right corner and select Invoice.
3. Use the Design and Content tabs to customize the template, such as adding logos, changing fonts, or including custom fields.
4. Assign a descriptive name to the template and click Done to save it.
5. Repeat these steps to create a second invoice template or "invoice mask.

Once you've created multiple templates, you can easily switch between them for a specific invoice.

Here's how:

1. Click the + New button and select Invoice.
2. Enter the customer's information and any other relevant details.
3. At the bottom of the invoice window, click the Customise.
4. Choose the desired template from the list of saved templates.
5. Finish by clicking Save and send or Save and close.

You can follow the same steps in creating multiple Quotes templates, just select Quotes instead of Invoice.

If you have additional questions regarding about your quotes and invoices, feel free to reply on this thread.