United States Postal Service
USPS offers multiple postal services which are used by people to send or receive their important mail items or packages at their homes or office. US Postal Service allow people to track their packages through the service called USPS Tracking which can be used from usps.com. You just need USPS Tracking Number to start tracking your packages online.
Apart from that, there are many other service such as USPS Change of Address which let people change their address with usps if they are moving to a new address permanently or temporarily. If you want to send your mail item at the earliest then use the fastest domestic service i.e. USPS Priority Mail. Also, check USPS Holidays and USPS Delivery Hours to get the estimated time of arrival of your package or mail item. To get confirmation of your order, you can use USPS Certified Mail service.