Most businesses will guard their actual marketing plan, as they don't want to make it public and share their plans and ideas.
The structure of a Marketing Plan should be detailed in your textbook, so i recommend looking at that, or referring to the biki. Most textbooks usually have an example.
From the syllabus:
elements of a marketing plan
• situational analysis including SWOT and product life cycle
• establishing market objectives
• identifying target market
• developing marketing strategies
• implementation, monitoring and controlling — developing a financial forecast, comparing actual and planned results, and revising the marketing strategy
There's some information on writing a business report in the
Jacaranda textbook which i've linked to which can assist you with structure. The
Biki also has some info on this.