Welcome and thanks for posting here in the Community. Allow me to step in for a moment and share some information about importing invoice template to QuickBooks Online (QBO).
The option to edit an imported custom invoice template is currently unavailable in QBO. For now, you'll need to edit the template through Word first before importing it to QBO again as a workaround.
Once done editing, here's how to import custom invoice template:
1. Click the Gear icon at the top. 2. Select Custom Form Styles under Your Company. 3. On the upper right, choose the New Style drop-down and select Import Style. 4. Click Browse, then select the template file. 5. Once done, select Next.
While this option isn't available yet in QBO, I'm going to submit feedback regarding this feature directly to our Product Developers Team for consideration in future updates. I also invite you to leave feedback as well. This can be done directly through your account by clicking the Gear icon in the top right corner, then select Feedback or by going to the following link: QuickBooks Online Feature Requests.
That's it! I'd be glad to continue assisting if you should have any additional questions. Take care and enjoy the rest of the week.