Let me share a few information, SuperStar777.
When you create an invoice template, it will only let you add one line item. It's for mapping purposes.
However, when you create the transaction in QuickBooks Online and select the imported template, it will support multiple items.
I'll include the invoice tutorials to guide you: QuickBooks Online - Invoicing and quoting tutorials.
If there's anything else that you need, feel free to let us know. We'll be right here to help you. Take care!
