Get the free Informed Delivery® feature to receive automated notifications on your packages Learn More Service / Sample Number USPS Tracking® 9400 1000 0000 0000 0000 00 Priority Mail® 9205 5000 0000 0000 0000 00 Certified Mail® 9407 3000 0000 0000 0000 00 Collect On Delivery Hold For Pickup 9303 3000 0000 0000 0000 00 Global Express Guaranteed® 82 000 000 00 Service / Sample Number Priority Mail