One paragraph elevator pitch for the idea. If someone only had 30 seconds of attention, and this is the only thing they read to get interested, what would you tell them? Think about what key points might excite a prospective investor, and what about the "why" behind the idea makes it most compelling.
Link your financial model here. Different businesses will require a different model. There are templates available online to use as a starting point. Some examples can be found here. Much of a typical financial model ends up needing adjustment after the business begins operating, however the exercise demonstrates to investors your thought process, self-awareness and thoroughness in analyzing your business.
Include projections and describe your assumptions if applicable. Some examples:
The purpose of the financial model is to detail costs and projected revenues over a period of time so that you and your potential investors can determine your capital needs and potential returns on that capital.