A concept note, also called a prospectus, is a preliminary description of the ideas behind a project. Businesses, academic programs, and nonprofit organizations use them to help test and refine concepts and to communicate about the project with potential readers, including partners and donors, supervisors, or review boards or committees.
In education, a prospectus may be used by students embarking on research to gather and present preliminary ideas: to review a field of study, state a research question, identify methods, and indicate the significance of a line of research, often including a budget and timeline.
The size of a concept note depends on many variables, but some feel that shorter is better. There is no fixed format. It mainly depends on requirement of the sponsor.