Tracking number or tracking code is a unique number assigned to each package, which allows you to monitor the movement of the parcel between the countries or even inside one country. Other shipments can be delivered by courier, transport and logistics companies, and how tracking codes look can vary a lot: CTAFT0000160477YQ, UPAAB000000251682107, AEL10105033654UA, SGADN143797855. Such packages are not always trackable in the recipient's country, and you'll have to wait for notification from the Post Office or a call from a courier company.