input multiple check box data to database

I created a form with multiple checkboxes to add to database, what do I need to change in the VALUE $_POST[penerima] to enter multiple checkboxes data into the database?

if(isset($_POST['simpan'])){
$simpan = mysqli_query($koneksi, "INSERT INTO umum (tanggal_terima, pengirim, no_surat, perihal, disposisi, penerima )
                                VALUES ('$_POST[tgl_terima]',
                                        '$_POST[pengirim]',
                                        '$_POST[no_surat]',
                                        '$_POST[perihal]',
                                        '$_POST[disposisi]',
                                        '$_POST[penerima]')
                                        ");