WooCommerce USPS Shipping Method:
WooCommerce extension for USPS Shipping is very much similar to the other shipping extensions. It uses USPS API so your customers can use USPS shipping service for their products. Your base currency should be US Dollars and your base country should be either the US, US Virginia Islands or Puerto Rico.
If your base country is any of the above, you can use it to ship your product in any country. You need to just fill up the details in the back end and you are ready to go. Your customer can choose the shipping method he likes on the checkout page.
You can configure shipping methods you offer, shipment packing type, box packing, sizes and weights in the back end which will be calculated automatically to decide shipping rates. You can also have a look at offerings like UPS Shipping Method, FedEx Shipping Method, and Australia Post Shipping Method.