There’s no one-size-fits-all for business plans. It’s worth doing a bit of research into the different types, and then cherry-picking the parts that are most appropriate for your business.
For example, a one-pager is a very concise business plan that’s only meant to cover the most top-level elements. It should be easy to understand at a glance.
A startup plan, on the other hand, is specifically written for new businesses. It often has a bigger focus on financials and market research.
A strategic plan, meanwhile, is one that takes a longer-term look at your business and includes forecasts that look further ahead.