Dear Mrunali,
To give you a summarized view on this, HR plays a vital role in strategy formulation, which begins with the strategic analysis stage. Here, they identify business goals, external opportunities, and competitive advantages. They are also expected to conduct environmental scanning to identify people-related business issues. Furthermore, HR must play a role in clarifying performance expectations and future management methods. At this stage, a business mission is determined, and action plans and resource allocations are set. HR strategies, objectives, and action plans must coincide with and ensure the business strategy is carried out.
Then comes the step of implementation.
Also, I have a document on this. Please check.