how to do zip in php

// Create a new ZipArchive object
$zip = new ZipArchive();
$zipname = 'example.zip';

// Open the zip archive for writing
if ($zip->open($zipname, ZipArchive::CREATE) !== TRUE) {
    die('Could not open archive');
}

// Add files to the zip archive
$zip->addFile('file1.txt');
$zip->addFile('file2.txt');

// Close the zip archive
$zip->close();

// Download the zip archive
header('Content-Type: application/zip');
header("Content-Disposition: attachment; filename=$zipname");
header('Content-Length: ' . filesize($zipname));
readfile($zipname);