An insertion order is a document that outlines the terms and conditions of an advertising campaign between a publisher and an advertiser. It serves as a formal agreement, detailing the specific ad placements, dates, and costs for the campaign. This document ensures that both parties are on the same page and helps to avoid any misunderstandings or discrepancies. Insertion orders are commonly used in the world of digital advertising, but can also be used for traditional media such as print or television. They provide a clear and organized framework for executing successful advertising campaigns and are essential for maintaining a professional and efficient relationship between publishers and advertisers.