A postbox is a public mailbox where people can drop off their outgoing mail. Typically found on streets or in public areas, postboxes are designed to securely collect letters and small parcels for delivery by postal services. They are often painted in bright colors, such as red or blue, to make them easily recognizable. Postboxes are an essential part of the postal system, which includes organizations like the United States Postal Service and Royal Mail. They help facilitate communication by allowing individuals to send letters and packages to friends, family, and businesses across various locations.