AnoopKrishna You can include the below code inside the correspondence. Change PROPERTY_ID with respective operator ID which contains link value.
You can add custom CSS styles for the a tag to look like buttons.
<a href= "<pega:reference mode="javascript" name="PROPERTY_ID"></pega:reference>">Approve</a>
<a href= "<pega:reference mode="javascript" name="PROPERTY_ID"></pega:reference>">Reject</a>
The above code renders as link.
Let me know if you have further queries.