Which processing category do postcards fall under?

Postcards are classified under the letter processing category. This classification is based on the dimensions and characteristics of postcards, which typically fall within specific size and weight limits set by postal regulations. Letters are generally defined as items that can be processed in a flat position and meet criteria regarding thickness and weight, which postcards do.

Postcards are designed for mailing without an envelope and usually adhere to the standard letter size limitations. This makes them eligible for the letter category, allowing them to be processed efficiently through the postal infrastructure designed for letter-sized mail. Understanding these classifications is critical for accurate postage and handling, ensuring that postcards are sent using the appropriate service and receive timely delivery.