Since the "Bill to Parent" option is currently unavailable in QuickBooks Online, as a workaround, you might want to remove the Bill to segment and put them back once the invoices are sent.
This sounds like a nice thing to have this option. I'll take note of this and add it to our list of ideas. While that feature isn’t currently in our development roadmap, we are working on big improvements that will be helpful for the majority of our customers, and you’ll see those rolling out soon through our QuickBooks Blog.
In case you need help with utilizing your sales forms templates in QuickBooks Online as well as on what other information you can add, you can go through the resources below:
Drop me a reply below if you have any other questions about invoices or anything QuickBooks related concerns. Have a great rest of your day.