<div class="wrap">
    <h1><?php _e( 'Configring for Plugin.', 'NearbyFacilities') ?></h1>
<?php if ( $message ) {
?>     <div class="updated">
        <?php echo esc_html( $message ); ?>
    </div>
<?php } ?>
    <h3><?php _e( 'Registration of Google Maps API key.', 'NearbyFacilities' ) ?></h3>
    <form action="" method="post" id="my-submenu-form">
        <?php wp_nonce_field( self::CREDENTIAL_ACTION, self::CREDENTIAL_NAME ) ?>
        <p>
            <label for="api_key"><?php _e( 'Google Maps API key', 'NearbyFacilities' ) ?>: </label>
            <input type="password" name="api_key" value="<?php echo $api_key; ?>" />
        </p>
        <p><input type="submit" value="<?php _e( 'Register' ) ?>" class='button button-primary button-large'></p>
    </form>
</div>