However, it is also possible to divide technical reports into two basic types based on the way they are presented. Informal reports may be any of the functional types mentioned above, but what makes them informal is that they are written in the form of memo and are addressed to someone inside the organization.
A formal report, on the other hand, has a cover letter, a title page, an abstract, a table of contents, an introduction, several sections in the body, conclusions, recommendations, appendices or annexes, and references. These reports, as with the informal reports, can be of any of the functional types mentioned above. What distinguishes them from informal reports is the various subparts just mentioned. These are usually longer than informal reports, and they are for more formal occasions. They may be written to audiences within the organizations or to audiences outside the organization.