That feature is not available in our theme nor in ConvertPlus. You will need to search for 3rd party services. For example, it seems that Mailchimp does have something similar to what you have in mind:
I also did a Google Search which might be of a help on your research.
Bottom line you need to find a service which will send such a link to the client upon the subscription. The form and subscription part can be handled via ConvertPlus and the integration of it to the MailChimp:
Alternatively, you can use our Emails Forms plugin to integrate a form to the MailChimp service:
Sending a secure link to the client after the subscription is a feature which you should look into MailChimp itself.