If you want any action in your mail than you have to send a link through our code which redirect in to your website. You have to do code what you want to do when user click on
"Accept"
or
"Reject"
in your page only. Through mail you can only send the parameters what actually you want to do either it is
"Accept"
or
"Reject"
.
for example
<a href="http://www.yourwebsitename.com?att=acpt">Accept</a>
<a href="http://www.yourwebsitename.com?att=reject">Reject</a>
Note: It will be great if you send encrypted querystring, so that the user can't change anything.
This is the simplest solution i had given you. If you want button than you have to send your page through
action
used in
<form>
Thanks
Ashish