How to Setup the USPS Shipping Method in Magento 2. The USPS Carrier allows you to offer domestic and international shipping services on the ground or airway conveniently. This is the service of the United States government and is famous for its flat rate shipping for smaller size and lightweight items. Their USPS Priority service is one of the most popular eCommerce shipping methods in Magento because it is flexible.
Thus, what credentials you need to connect your Magento 2 store to the USPS serve.