<?php

/* Include the Composer autoload (PhpSpreadsheet must be installed via Composer) */
require_once '/path_to_composer/vendor/autoload.php';

/* Namespace use */
use PhpOffice\PhpSpreadsheet\Spreadsheet;
use PhpOffice\PhpSpreadsheet\Writer\Xlsx;

/* Create a new Spreadsheet object, for XLS files */
$spreadsheet = new Spreadsheet();

/* Select the active sheet */
$sheet = $spreadsheet->getActiveSheet();

/* This is how you set cell values */
$sheet->setCellValue('A1', 'Cell A1 content');
$sheet->setCellValue('B1', 'Cell B1 content');
$sheet->setCellValue('A2', 'Cell A2 content');
$sheet->setCellValue('B2', 'Cell B2 content');

/* HTTP headers to tell the browser we are sending an XLS file */
header( 'Pragma: public' );
header( 'Cache-Control: must-revalidate, post-check=0, pre-check=0' );
header( 'Content-Type: application/vnd.ms-excel' );
header( 'Content-Transfer-Encoding: binary' );
header( 'Expires: Mon, 1 Apr 1974 05:00:00 GMT' );
header( 'Last-Modified: ' . gmdate( 'D,d M YH:i:s' ) . ' GMT' );

/* Create the Xlsx object */
$writer = new Xlsx($spreadsheet);

/* Output the XLS file */
$writer->save('php://output');