Imbedded financial calculator on webpage

I have a excel investment viability financial model which I would like to build into my website. I want it to be printable so a client can input the fields and print the outcomes with my business logo and headings on it.

the page should only be visible to customers who sign up so I will need a sign-in page which issues a password to access the toolkit (investment model).

Webpage has been built in Wix.