I should have guessed this was too easy; of course the TV tag doesn’t work in the report form; it gets used as-is by eForm and never gets passed through the parser.
There are two ways to handle this; you can add a hidden field to the form, or use an event with a custom snippet to add to the $fields array so you can use a placeholder in the report. Personally, I’d go with the hidden field. You’ll be using the same form tpl for all the product pages, so it’s not a big deal.
<input type="hidden" name="pdf" value="[*pagetitle*]" eform="::0::" />
If you’re using a Hyperlink output widget for the TV, you don’t want to use the TV here since it generates a relative hyperlink, so the product’s pagetitle should do the trick. Now in the report tpl you can just put
<strong>Product: </strong>[+pdf+]
or whatever enclosing HTML will go with the rest of your report, using the placeholder for whatever you name that hidden input field as. Make sure to specify the non-validating eForm attribute, otherwise eForm will run a validation on all hidden input fields and complain if it’s different from the form tpl (and the actual value will of course be different from the original MODx tags) to protect from form hacking. Of course, if this were going into a database you would have to provide your own careful validation of its value for the same reason.