You have to go to a Post Office to register your mail. A barcode label will be affixed to each registered mail item and a copy of that barcode is given to the sender. Registering your mail gives you the reassurance that your item has been delivered. The service requests a signature from the recipient as proof that your item has been successfully delivered. For extra peace of mind, you may also insure your item. To view information on insuring your mail item, click here.
Detailed information about Registered Mail is available here.