1. Go to this page and download the library: Download easeappphp/hmac library. Choose the download type require.
2. Extract the ZIP file and open the index.php.
3. Add this code to the index.php.
<?php
require_once('vendor/autoload.php');
/* Start to develop here. Best regards https://php-download.com/ */
$message = "Hello!, I am creating a Signature with the HMAC Class";
$createdSignature = $hmac->createSignature("sha256", $message, $secretKey, true, true);