Automate variable invoice with Zapier

In the absence of custom fields for client details in Quickfile, I currently sign up new clients using a web form which they complete with all of their personal information. (Currently using Hubspot forms but this could change easily.) I then use Zapier to bring those details into Quickfile and automatically create a new client, ready for invoicing. This works fine.

I would like to take this a step further and have Zapier prompt Quickfile to issue a new invoice to that client directly, removing the need for me to get involved at all and minimising signup time. The trouble is, the invoiced amount always varies.

I could pre-populate a hidden field in the form, but I think that would mean it would have to be a different form each time, and so Zapier wouldn’t work because it wouldn’t know which form to retrieve.

My vision is a functionality where I enter only the new client’s email address and the invoice amount, and email that form to the client (or even better, click a ‘send’ button to do the same), and then they fill in all of the form details, which instantly generates and sends an invoice in Quickfile.

How can I do this?

You could use the API directly and have your own hosted form.