I want to include a link to a file for download once they complete the form.

I want to include a file for download once they complete the form. 

To clarify, you want to include a link to the uploaded file in your Thank you page?

You can add the upload link field in your thank you page.

Sample screenshot:

Hope this information helps.

If this does not answer your question, kindly give us more information regarding adding a link to the form.

Thank you.