overnight letter usps

overnight letter usps refers to USPS’s Priority Mail Express service, which guarantees overnight delivery for urgent letters, documents, and small packages. This service is ideal for time-sensitive materials like legal documents, contracts, and medical paperwork. USPS offers overnight delivery to most U.S. locations with tracking and insurance coverage. Delivery times can vary depending on the time of drop-off, but this service ensures that customers can send important letters with confidence that they will arrive the next business day.