USPS shows you how to send a letter or postcard in the U.S., from choosing an envelope, writing the address, buying and applying stamps, and finding a drop-off location.

Pack of 10 5-7/8" (L) x 10" (W) $0.00 Priority Mail® Forever Prepaid Flat Rate Legal Envelope Includes Customer's Return Address 15" (L) x 9-1/2" (H) $12.10

Shop our selection of Envelopes, Priority Mail Shipping Supplies on the USPS.com Postal Store

Envelopes Priority Mail® Forever Prepaid Flat Rate Legal Envelope Includes Customer's Return Address 15" (L) x 9-1/2" (H) $12.10

First-Class Mail is a fast, low-cost way to send envelopes and postcards. See First-Class Mail and Forever stamp prices for a letter and postcard.

Using the Priority Mail Flat Rate Envelope is quick and convenient. Send this envelope at a flat rate regardless of weight or destination. Order online at the Postal Store.

Compare USPS shipping options like Priority Mail Express, Priority Mail, First-Class Mail, and USPS Ground Advantage to find the service that's right for you.

Domestic Return Receipt Forms Pack of 10 $0.00 Priority Mail® Forever Prepaid Flat Rate Padded Envelope Includes Customer's Return Address 12-1/2" (L) x 9-1/2" (H) $12.85

Find tips for addressing mail properly to ensure timely and accurate delivery by USPS.

Compare USPS mail services by starting retail prices, shipping time, and more. Most services automatically include USPS Tracking ®, and you can add insurance and extra services.