<?php
// (A) LOAD PHPSPREADSHEET
require "vendor/autoload.php";
use PhpOffice\PhpSpreadsheet\Spreadsheet;
use PhpOffice\PhpSpreadsheet\Writer\Xlsx;

// (B) CREATE A NEW SPREADSHEET
$spreadsheet = new Spreadsheet();

// (C) GET WORKSHEET
$sheet = $spreadsheet->getActiveSheet();
$sheet->setTitle("Basic");
$sheet->setCellValue("A1", "Hello World!");
$sheet->setCellValue("A2", "Goodbye World!");

// (D) ADD NEW WORKSHEET + YOU CAN ALSO USE FORMULAS!
$spreadsheet->createSheet();
$sheet = $spreadsheet->getSheet(1);
$sheet->setTitle("Formula");
$sheet->setCellValue("A1", "5");
$sheet->setCellValue("A2", "6");
$sheet->setCellValue("A3", "=SUM(A1:A2)");

// (E) OUTPUT
$writer = new Xlsx($spreadsheet);

// (E1) SAVE TO A FILE ON THE SERVER
$writer->save("demoA.xlsx");
echo "OK!";

/* (E2) OR FORCE DOWNLOAD
header("Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
header("Content-Disposition: attachment;filename=\"demoA.xlsx\"");
header("Cache-Control: max-age=0");
header("Expires: Fri, 11 Nov 2011 11:11:11 GMT");
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
header("Cache-Control: cache, must-revalidate");
header("Pragma: public");
$writer->save("php://output");
*/