IT strategic planning processes need to be adequately documented and communicated for several reasons, but the most important one is to promote transparency to stakeholders. Transparency means being open, honest, and accountable for the actions and decisions of the IT department. Transparency helps to build trust, credibility, and confidence among the stakeholders, such as senior management, business units, customers, suppliers, regulators, and employees1. By documenting and communicating the IT strategic planning processes, the IT department can demonstrate how it aligns its goals and objectives with the business strategy, how it prioritizes and executes its projects and initiatives, how it measures and reports its performance and outcomes, and how it manages its risks and challenges. Documenting and communicating the IT strategic planning processes also enables the IT department to solicit feedback and input from the stakeholders, and to address any issues or concerns that may arise23.
The other options are not as important as promoting transparency to stakeholders. Justifying spending on IT projects is a benefit of documenting and communicating the IT strategic planning processes, but it is not the primary reason. Ensuring other departments are aligned with the direction set by IT is a result of documenting and communicating the IT strategic planning processes, but it is not the main purpose. Informing business units of IT department achievements is a part of documenting and communicating the IT strategic planning processes, but it is not the most important reason.
References: 1: Creating an IT Strategy Communications Plan: 5 Keys to Success4 2: IT Strategy Template for a Successful Strategic Plan | Gartner1 3: 14 Ways To Document Communications Processes For Faster ... - Forbes