This plugin offers shipping rates by USPS. The United States Postal Service(USPS) is an independent shipping agency of the United States federal government which provides convenient and affordable shipping and mailing services in the US (United States) and internationally. The USPS shipping services ship products to more than 180 different countries all over the world. This is a cost effective shipping solution which calculates price according to the size, weight and distance. The customers can track their order using the USPS tracking number from the USPS website.
More information about the USPS can be found on their official website here: https://www.usps.com/