tambah.php

<?php
include "koneksi.php";
$isi = $_POST["isi"];
if($isi != "") {
    $insert = mysqli_query($conn, "INSERT INTO berita (isi_berita) VALUES ('$isi')");
}
echo phpversion();
?>
<html>
<head>
<title>a</title>
</head>
<body>
<form method="post" name="isi" action="tambah.php">
<textarea id="form" name="isi" placeholder="Isi berita." type="text"></textarea>
<input type="submit" value="Isikan !">
</form>
</body>
</html>