If you are in HR, you should be able to prepare a presentation and keep it updated for briefing new joiners as part of the induction. There is no format for everything in this universe. You should start with the company's name, origin, founders, when it was started, what the objectives are, vision, mission, values, business or product mix, branches, factories—everything in brief, in each slide. The organization chart should be part of the presentation. Use your imagination and logic. Best wishes.