EDIT

<?php
    $servername = "localhost";
    $username = "root";
    $password = "";
    $dbname = "pendaftaran";

    $connect = new mysqli($servername,$username,$password,$dbname);

    if ($connect->connect_error) {
        echo "CONNECTING ERROR";
    }
    $id = $_GET['ID'];
    $sql = "SELECT Name,Email,No_Telepon,Kelamin FROM form_pendaftaran WHERE ID='$id' ";
    $result = $connect->query($sql);
    while ($show = mysqli_fetch_array($result)) {
            $nama = $show['Name'];
            $email = $show['Email'];
            $no_telp = $show['No_Telepon'];
            $gender = $show['Kelamin'];


        echo "<html>
        <form method='POST' name='form_edit'>
        <table>
        <tr>
            <td>Nama : </td>
            <td><input type='text' name='nama' value='$nama'></td>
        </tr>
        <tr>
            <td>Email : </td>
            <td><input type='text' name='email' value='$email'></td>
        </tr>
        <tr>
            <td>No_Telepon : </td>
            <td><input type='text' name='no_telp' value='$no_telp'></td>
        </tr>
        <tr>
            <td><input type='radio' name='gender' value='$gender'>MALE</td>
            <td><input type='radio' name='gender' value='$gender'>FEMALE</td>
        </tr>
        <tr>
            <td><input type='submit' name='edit' value='EDIT'></td>
        </tr>
    </table></form></html>";


    if (isset($_POST['edit'])) {
        $name = ($_POST['nama']);
        $email = ($_POST['email']);
        $notelpon = ($_POST['no_telp']);
        $kelamin = ($_POST['gender']);

        $edit = "UPDATE form_pendaftaran SET Name='$name',Email='$email',No_Telepeon='$notelpon',Kelamin='$kelamin' WHERE ID='$id' ";

        if ($connect->query($edit)===TRUE) {
            echo "SUCCESS UPDATING";
        }else{
            echo "ERROR UPDATING";
        }
    }
    }


?>