You'd probably need to make a hidden page on your site with a link to the download, then use that as the thank you page for a contact form on your site. I'd also make the thank you page hidden from search engines, and give it a name that would not be easy to guess.
Is this the only way? Has there been an app developed to do this for service industries? With the method you mentioned it will be diffcult to track the number of downloads a file has. Say for instance the person decides to just mark the page as favorite or AirDrop the page to someone and we wouldn't know how many times it was downloaded.
I agree it's not ideal for that reason. Another way to do it would be to have a digital product and create a coupon for 100% off that could be used with it. If you make the coupon code something gibberishy it would lessen the chance that someone would share it. You can also limit the download to only one time.
