us post office overnight letter

us post office overnight letter refers to the USPS Priority Mail Express service, which allows individuals and businesses to send documents overnight with guaranteed delivery and tracking. This is useful for time-sensitive paperwork, legal notices, and high-priority correspondence. Fulfillment centers offering document services must prepare and ship such letters with precision, ensuring compliance with size and packaging guidelines. The service includes insurance and proof of delivery, making it a reliable choice for critical communication.