Things You'll Need
Instructions
Measure the postcard to ensure it is the correct size, as defined by the United States Postal Service. Not all single sheet paper mailpieces are qualified to be mailed as postcards at the First-Class Mail price set by the USPS. To qualify, a postcard must be rectangular in shape, a minimum of 3.5 inches high by 5 inches long and less than one inch thick and a maximum of 4.5 inches high by 6 inches long. Postcards that do not meet the defined sizes are considered letters by the USPS, and letter-sized charges will apply.
Address the postcard. Postcards are often designed to include a blank area on the back of the card to include the recipient's address and a short message. Write down the recipient's full name, street, state, city, and zip code.
Check the required postage price. The cost of mailing a postcard can vary depending on its destination and size. The United States Postal Service websites provides a short guide to postcard pricing, and offers postcard stamps specifically designed to be mailed with postcards available via their online store or in-person.
Apply the postage to the postcard. Gently lay the self-adhesive stamp to the top right corner of the card's non-pictured side along with the address and persona message.
Mail the postcard. Postcards can be dropped into any delivery mailbox owned by the USPS or given to a clerk at any USPS post office location.