In which phase should the activity "Document the Information Security Policy" primarily occur?

The activity "Document the Information Security Policy" should primarily occur in the Plan phase because this is when the foundation of the information security management system (ISMS) is established. During the Plan phase, organizations define their information security objectives, scope, and the specific policies that will guide their security practices. Documenting the Information Security Policy is crucial in this stage as it outlines the organization's approach to managing information security risks and serves as a framework for subsequent actions.

In the Do phase, the focus shifts to the implementation of the processes and controls defined in the Plan phase, ensuring that the policy and other procedures are put into action. The Check phase involves monitoring and reviewing the performance of the ISMS against the policies and objectives set during the Plan phase, which assesses the effectiveness of the policies in place. The Act phase centers on continual improvement, where any necessary changes to the policies or procedures are made based on the findings from the Check phase. Thus, documenting the Information Security Policy aligns best with the activities associated with planning and establishing a robust ISMS.