Hello there, @bgreiner.

Allow me to join the thread and provide some information about this

Currently, adding variables in QuickBooks Online isn't available. However, you have the option to customize your template as mentioned by my colleague above.

On the other hand,  I’ll surely pass this preference to our developers so they can work on making your experience as user-friendly as possible in the future. 

 Also, you can always visit the QuickBooks Blog site to check the latest feature added to the application.

Please let me know if you have any other questions with QuickBooks. I'm here to help you out. All the best!