What is required for all documents containing originally classified information?

The requirement for all documents containing originally classified information is the use of standard markings. These markings serve multiple purposes: they indicate the classification level of the information (such as confidential, secret, or top secret), they inform individuals about handling procedures and limitations, and they ensure that the information is correctly managed and protected according to its classification. Standard markings help in safeguarding sensitive information by providing clear, consistent visual cues that signal the level of protection required, thus contributing to effective information security practices. This is essential for meeting compliance with national security regulations and ensuring that all personnel understand the classification and handling required for such documents.