kirim.php

<?php
if($_POST['kirim']){
    $admin = 'fyn250976@gmail.com'; //ganti email dg email admin (email penerima pesan)

    $nama   = htmlentities($_POST['nama']);
    $namail = htmlentities($_POST['namail']);
    $judul  = htmlentities($_POST['judul']);
    $pesan  = htmlentities($_POST['pesan']);

    $pengirim   = 'Dari: '.$nama.' <'.$namail.'>';

    if(mail($admin, $judul, $pesan, $pengirim)){
        echo 'SUCCESS: Pesan anda berhasil di kirim. <a href="index.php">Kembali</a>';
    }else{
        echo 'ERROR: Pesan anda gagal di kirim silahkan coba lagi. <a href="index2.php">Kembali</a>';
    }
}else{
    header("Location: index2.php");
}
?>