A segment of a longer tracking ID used by couriers.

Where did you (on a package, a form, or a letter)? Which country are you sending to or receiving from?

Post Code: The value is not a valid postcode. - Gelato Create

In the context of shipping and mail, a 6-digit number like 141953 is typically used for:

The form expects 4 digits (AU) or 5 digits (US).

Are you trying to or fill out a shipping address ? Windsor Postcode - Australia Post