Set up a downloadable file in form?

Good afternoon. How to make the form that the client downloads the file if a user clicks on the button?

If I understood your concern correctly, you would like to provide a download link that the user will click to download a file? Is that correct? We do not have an auto download feature that triggers when the "Submit" button is clicked. 

However, you can still provide the download link to your users after submitting the form. Note that you need to upload your form on a cloud storage provider like Dropbox, Box.com or Google Drive where you can get the download link.

1. First, you can add the download link in your "Thank You" page. To know more about this feature, you can check this guide: https://www.jotform.com/help/211-Setting-Up-the-Thank-You-Page. On my screenshot below, you can see how I do that: 

2. Now you can anchor the link to a text so it will be clickable, here's a screenshot showing on how I'm adding mine: 

Another way that you can do this is by adding the download link in your form's autoresponder email. To learn more about the email alerts, you can check this guide: https://www.jotform.com/help/30-Explanation-of-Email-Notification-and-Autoresponder-Settings. 

I hope this helps. Let us know if I misunderstood your concern.