Payment summary also called PAYG (Pay as you go) and contain all same details in the document.
The Payment summary is signed by the employer. The employer may issue a receipt, remittance advice or group certificate.
If you are doing job on tax and received tax withheld and in case, you have lost or did not receive of your payment summary, you can contact to your employer and ask for copy of payment summary.
Employer must to notified to ATO regarding the amounts of withheld tax of income. So, ATO can make cross verification about withheld tax and income on your tax return when you lodged, to make sure that your employer put correct withheld amount or not in your Payment summary