Office stamp is a tool used to mark documents as official. It usually consists of a rubber stamp with the company's name, logo, and other information. The term 'PAID' is often used to indicate that a payment has been made, while 'DATER' is used to indicate the date on which the document was stamped. Finally, 'RECD' is used to indicate that the document has been received. All three terms are commonly used in office stamps.