Online postage is a service that allows individuals and businesses to purchase and print postage labels from their computers or mobile devices. This eliminates the need to visit a post office, making it convenient for shipping packages and letters. Users can select the type of service they need, such as USPS, FedEx, or UPS, and pay for postage online. Once the postage is purchased, users can print the label at home and attach it to their package. Many online postage services also offer tracking options, allowing senders to monitor their shipments until they reach their destination.