What online platform allows USPS customers to access various postal services?

The online platform that allows USPS customers to access various postal services is USPS.com. This site serves as the official online presence of the United States Postal Service, where customers can find a wide range of services such as tracking packages, purchasing postage, scheduling pickups, and finding locations. The functionality of USPS.com is specifically designed to meet the needs of USPS customers, making it the go-to resource for postal services online.

Other options like ShipNow.com, PostalService.net, and MailTracker.org do not serve as official USPS websites or provide similar comprehensive access to postal services. They may offer related services, but they do not provide direct access to the broad array of USPS functionalities that USPS.com does.