I've question like this title: I want to add into(body messages) every email coming to mail gateway (Ironmail) to make a notification like "If this email you received is Spam mail please click here : firstname.lastname@example.org"
When end user click email@example.com , this action will send that email to admin and admin add this email into black list.
You will need to do this as a HTML message stamp, as plain text will not provide the functionality that you are looking for. I would start by wrapping the whole thing in paragraph tags so that it is displayed properly. The email link can be just a normal mailto anchor tag.
<p>If this email you received is Spam mail please click here: <a href="mailto:firstname.lastname@example.org?Subject=Spam%20message">email@example.com</a></p>
Note that this will have the user compose a new email message, but with the to and subject fields pre-populated. This will not include any information about the alleged spam message, and there is no way to include that.