SELECT *  FROM event_table JOIN package ON event_id WHERE cusact_id = 8 AND event_id=80

$c_id = $_SESSION['u_id'];
$n_id = $_GET['n_id'];
$p_id = $_GET['new_p_id'];

<?php
 session_start();

  include_once 'order.confirmation-header.php';

  include 'includes/dbh.inc.php';


$c_id = $_SESSION['u_id'];
$n_id = $_GET['n_id'];
$p_id = $_GET['new_p_id'];

    $sql = "SELECT event_id, event_name, event_date, event_time_start, event_time_end, cusact_id, theme, reserve_date, reserve_time  FROM event_table as e INNER JOIN package as p ON e.package_id = p.package_id WHERE cusact_id = $c_id  AND event_id=$n_id";
    $data = mysqli_query($conn, $sql);


if(!$data){
        echo("Error description: " . mysqli_error($conn));
    }