what is us postal service first class mail

what is us postal service first class mail refers to the most economical and commonly used mail service offered by USPS for sending letters, postcards, and lightweight packages. It includes delivery within 1–5 business days, with options for tracking and limited insurance. First-Class Mail is ideal for personal correspondence and small parcels under 13 ounces, making it a cost-effective choice for everyday mailing needs across the U.S.