When you create a link with Action of "Email Extension", it will automatically put the form variables into the body of the email. This is the job of the Email Extension.
You can actually have fine control over this: On the Action tab, you will see a set of checkboxes (under the Settings button) - these are the variables that will be included in the email. If you tick any screen, or tab, then all the variables from that screen and below will be added to the email. Tick a tab, and all variables from that tab will be added to the email.