Tracking numbers are used when it comes to shipping. When packages are being shipped, the packages would be assigned numbers for the purpose of recognition. There are some deliveries that are really time-sensitive, and tracking numbers help in knowing the location to where they should be delivered.
This number is always a unique identification code or number that is assigned to a parcel or package. The shipping label has this tracking number on it in form of a bar code, and this bar code can be scanned by anybody with a smartphone or bar code reader.
Some examples of carriers that make use of the tracking number in the United States include FedEx, UPS, and the United States Postal Service. Most European Postal Services, as well as the United States Postal Service, make use of the S10, which is the UPU standard for mailings that are going outside the country.