What is the purpose of portion markings in a document?

Portion markings serve the important function of designating the classification levels of individual sections within a document. In the context of classified information, it is crucial to identify the specific classification level that applies to each part of a document, as certain sections may contain sensitive information that requires protection at different levels of classification, such as confidential, secret, or top secret. This practice allows users to handle the information appropriately, ensuring compliance with security protocols. By applying portion markings, it becomes clear which portions of the document are classified and at what level, thereby facilitating proper access, dissemination, and safeguarding of sensitive information.