us postal overnight letter

us postal overnight letter refers to sending time-sensitive documents using USPS Priority Mail Express. This service guarantees overnight delivery to most U.S. locations, includes tracking, and offers delivery even on Saturdays for an extra fee. Common use cases include legal papers, medical documents, and contracts. The sender must meet cut-off times at the post office to ensure next-day delivery. USPS provides flat-rate envelope options ideal for letters and forms.