Following are my code that return expiry time of token and some other login info.
include_once('vendor/copyleaks/php-plagiarism-checker/autoload.php');
use Copyleaks\Copyleaks;
$copyleaks = new Copyleaks();
$loginResult = $copyleaks->login('xxxxxxxx@gmail.com','My-Api-Key Here');
echo json_encode($loginResult);
It depends on what are you trying to scan.
You can follow the example found at:
https://github.com/Copyleaks/PHP-Plagiarism-Checker/blob/master/demo/demo.php
and the Copyleaks API documentation: