us postal service priority The U.S. Postal Service Priority Mail is a fast and reliable shipping option for domestic and international deliveries. Priority Mail offers delivery in 1 to 3 business days within the United States, with guaranteed delivery timeframes for certain services like Priority Mail Express. This service includes tracking, free shipping supplies, and insurance coverage for packages up to $100. It is an ideal choice for shipping items that require timely delivery but don’t need the expedited speed of express services. USPS Priority Mail is commonly used by businesses and e-commerce sellers to ensure customer satisfaction with quick, affordable shipping options.