Buttons in Table using PHP/SQL Loop

I have this piece of code:

<?php $res = $conn->query("SELECT * FROM users");
    //If the result of the query has more than 0 rows (1 or more) continue to the loop
    if(mysqli_num_rows($res) >0){
        //Loop to organise the data
        while($row = mysqli_fetch_array($res)){
            if($row['permission'] == "2"){
                 $perms = '<span class="label label-danger">Administrator</span>';
            } elseif($row['permission'] == "1"){
                 $perms = '<span class="label label-success">Registered User</span>';
            } else {
                 $perms = '<span class="label label-warning">Awaiting Approval</span>';
            }


            //Return the table data
            echo "<tr><td>" . $row['firstname'] . "</td><td>" . $row['surname'] . "</td><td>" . $row['email'] . "</td><td>" . $row['username'] . "</td><td>" . $row['telephone'] . "</td><td>" . $perms . "</td>";

        }
   }?>

What I want is to add a button in a new column for every row that will activate a piece of code to delete the record in the db.

was wondering if someone could assist or point me in the right direction on how to do this. Eventually, there will be a delete button and an approve button that will activate different pieces of SQL code located in the same file. Thanks