Can I add a downloadable file when someone signs up?

If you have the downloadable link ready, you can add/insert it in the Text field on your form. You can also add/insert it in the Thank You page or autoresponder email template. We have a complete guide on how to achieve this. Here's the link: https://www.jotform.com/help/431-How-to-Add-a-Downloadable-File-to-Your-Form

To my understanding, you want to share a downloadable file when someone signs up. You can try adding/inserting the downloadable link in the Autoresponder email or in the Thank You page. (Please see section B and section C on the guide I have provided)

Please give it a try and contact us again if you have questions.