Is it possible to send an email to the customer upon registration?

How do I setup mailchimp to respond to customer's newsletter subscription (in this case a short pdf doc) with Mailchimp "Thank you confirmation page"? In mail chimp I set this page to have a downloadable url where customer can click and download content.  

Now the page Mailchimp sends is the "reCAPTCHA" page under form builder.  

Thanks!

You can set up an autoresponder email with JotForm, this will be triggered as soon as the user submits the form, you can include any desired links and attachments in the email, this guide will help you setting that up: https://www.jotform.com/help/26-Setting-up-an-Autoresponder-Email 

Note that this is set up on the JotForm form builder, you still need to integrate your form with MailChimp in order to have submissions added to your list, this guide will provide you more details about how our integration currently works: https://www.jotform.com/help/163-How-to-Integrate-with-MailChimp 

Now, if you want to specifically send the email from MailChimp, then that would not be possible from JotForm, since emails cannot be triggered on that way, you will need to check with MailChimp instead if you can send the email once a record is added to a MailChimp list.