The details of the customized field have to be entered manually, mark124.
The pre-fill option is only available when creating an invoice. Rest assured, I'll take note of this product suggestion and share it with our Development Team.
The enhancement of our product comes from the ideas of our customers. With that said, our developers will analyze this one and may be added as one of our new feature release.
You can also visit our blog to know what's new with QuickBooks Online.
If you're ready to convert an estimate into an invoice, you can check this article: Convert an estimate into an invoice.
I will always be right here ready to help you!
