There are 2 things here. 

When do you want to send correspondence? After capturing Data in section and clicking submit?

What is this Hyperlink? Are you expecting something like Outlook on click of email address directly it will take you to the body section of a new email thread?

if its just a section which has Hyperlink, on click of hyperlink call a local Action, Local action would have section with a property to capture the content of the email (more chars - text input). On click of submit as a Post activity call the OOTB activity to send correspondence. You can also refer this property (only used capturing the content of the email in this process) in Correspondence rule which will be used for Send Email smart shape if you are in the flow.