Postcards or postcards are rectangular thick paper or cardboard used for writing and mailing without envelopes. You can also use shapes other than rectangles. There are also some novel exceptions, such as wooden postcards made of thin wood, copper postcards sold in copper Township, Michigan, and coconut "postcards" from tropical islands.

In some places, postcards can be sent at a lower price than letters. Collectors distinguish between postcards (postage stamps) and postcards (postage prepaid postcards). Postcards are usually printed by private companies, individuals or organizations, while the relevant postal authorities issue postcards.

The oldest postcard in the world was sent to Theodore hook in 1840. Postcard research and collection is known as "epidemiology.".

Collecting postcards is a widespread hobby. The value of a postcard depends largely on the image displayed on it. For collectors, other important factors may be the country, the issuer, and the author. Online catalogs can be found on collectors' websites and clubs. These directories provide detailed information about each postcard and its pictures. In addition, these sites include collection management tools, trading platforms and forums to assist in discussions among collectors.

Old photo postcards are the main original record of the location. Postcards record the natural landscape and architectural environment, including buildings, gardens, parks, cemeteries and tourist attractions. Postcards also commemorate major events, popular humor and many other aspects of everyday life - transportation, entertainment, sports, work, religion or advertising. Postcards can also help you understand how to adopt, adapt and discard new forms of communication media. Museums and archives have a large collection of picture postcards; many of them are digital

Professional marketing companies in many countries produce and distribute free advertising postcards. These are usually provided on line display shelves in squares, coffee shops and other business places, and are not intended to be mailed.