Any mail with certified, expedited shipping, or paid through Kal-Stamps will have a tracking number. This tracking number is always in the QR code of the parcel. This tracking number can be sent to the recipient so they can track their parcel, and have an idea of when it will be delivered to their address. Using standard postage does not have a tracking number (unless with Kal-Stamps), so one of the other services will have to be used for tracking. If one is regularly finding the need to track letters, then they may want to sign-up for Kal-Stamps.