Most corporations have strategic plans. The most common format is SWOT: strengths, weakness, opportunities, and threats. This implies an analysis of their competitors as well as the long-range business environment. Most in individuals develop a simpler business plan that documents their financing, organization, marketing, and positioning. When I was consulting entrepreneurs in marketing, I discovered software programs that provide templates to prepare a business plan.
If you are hired or assigned to write a strategic plan, I wish you good luck. First-of-all, you're going to be involved with several people because no one person has all of the information nor can make all of the decisions in developing a strategy. This is a very specialized field of business writing that requires an understanding of the relationships among goals, objectives, strategies, and tactics. I suggest that you start with a spreadsheet rather than an outline.
The feds have a formal process of "consensus" building where they put flip charts around the room (or in small groups) and "brainstorm" for ideas and input. The most "votes" make the list, and the list gets narrowed down to eliminate overlaps and duplications. Most businesses don't operate that way. The board sets the policies and makes the decisions to be implemented by the staff.