whats first class mail

whats first class mail refers to a category of mail services offered by USPS. First-Class Mail is an affordable shipping option for letters, postcards, and small packages that are typically under 13 ounces. This service offers delivery within 1 to 3 business days, depending on the destination. First-Class Mail is often used for non-urgent, everyday correspondence and is one of the most commonly used services for light packages and personal letters.