Ah, I see - you want the "lead" to be able to submit a file which is then emailed to your company right?
This would require some custom coding which displays a file selector on your landing page, uploads the submitted file to some web server, and sends the email containing the file. You'll certainly need a web developer for this task.
A quick, temporary solution would be to simply direct the user after submitting the form to a page with a mailto:yourcompany@company.com on it, so they can send you the file directly.