what is priority mail usps refers to a USPS shipping service that offers fast delivery within 1-3 business days for domestic packages. It includes tracking, up to $100 insurance, and free packaging supplies. Priority Mail is often used for small businesses and e-commerce sellers who want a balance between speed and cost. It’s ideal for shipments weighing under 70 lbs and priced based on weight and zone. Understanding what is Priority Mail USPS helps consumers and businesses choose reliable and timely delivery options without paying premium express fees.