The current HS invoicing system does not support raising pro-forma invoices for customers, which can then be converted to final invoices. There is an option to share the draft invoice with the client but there is no way to edit the title or invoice presets to clearly define that this is a proforma invoice.
The work-around we have found is to create a quote template titled pro-forma, and we clone the existing cmr quote to the pro-forma template. However, that is not the best solution since we end up having two quotes in the deal for the same amount, which messes up our numbers reports, thank you.