Thanks for checking in with us. Let me provide some other options on how to customize your invoices, cactus.
The option to show the open balance in the text along with the invoice number is unavailable. However, you can customize the invoice to show the Account summary. This gives you the current total account balance and all payments or credits on the customer's last invoice.
For the steps and details, you can check out this article: Add an account summary to an invoice in QuickBooks Online.
You can also add custom fields to the template and manually enter the opening and closing balance when creating an invoice. Just refer to this article for more details:
How to add custom fields to invoices.
If you have an invoice template from your DOCX template, you can import the custom from styles into QuickBooks Online (QBO). This helps reflect your brand identity into your sales forms.
We have a link here that contains all the articles you need about managing customers' transactions and income: https://quickbooks.intuit.com/learn-support/manage-customers-and-income/misc/02/manage-customers-and....
Keep me in the loop if you need a hand with managing your invoices or any QBO related. I'll be here to help.
