Thanks for coming in the Community, @k-r-ivory-aol-co.
To clarify, are you referring to your QuickBooks Desktop (QBDT) 2018 invoice template? It has some slight differences compared to QuickBooks Online (QBO) since they both run on different platforms. Though, you can still create and import your personalized form styles in QBO. For additional information about this process, please refer to this article: Import custom form styles for invoices or estimates.
On the other hand, if you require to create a copy of your old invoice template created in QBO, you may need to
Here's how to start a new custom form style:
- Go to the Gear icon.
- Under "Your Company," choose Custom Form Styles.
- Select New Style.

- Pick the type of form you would like to create and customize.
Additionally, to give you more ideas on how to create attractive and professional-looking sales forms, check out this article: Customize invoices, estimates, and sales receipts in QuickBooks Online.
Fill me in should you need further assistance in re-creating your invoice. I'm always available here to help.