Postal stamps are small pieces of paper issued by postal services that indicate the prepayment of postage for sending mail. They usually feature images, designs, or symbols that represent a country, culture, or significant event. Stamps come in various denominations and can be used for different types of mail, such as letters and packages. When a stamp is affixed to an envelope or parcel, it serves as proof that the sender has paid for the delivery service. Collecting stamps, known as philately, is a popular hobby for many people around the world, as it allows them to appreciate art, history, and culture through these tiny pieces of paper.