What does the stamped information mean on the front of a envelope?

The stamped information on the front of an envelope typically includes the postage, which indicates that the sender has paid for the delivery of the mail. It may also display a cancellation mark, which shows that the stamp has been used and prevents it from being reused. Additionally, there can be a date and post office information, indicating when and where the mail was processed. This information helps postal services in sorting and delivering the envelope to its intended destination.