Informal business reports include information reports, progress reports, justification/recommendation reports, feasibility reports, minutes of meetings, and summaries. Formal reports are formatted on plain paper with manuscript design, whereas routine reports may be formatted on prepared forms. Formal reports are much longer and necessary for major investigations and research such as report proposals and research methods. Informal reports include short memos/letter format, and are in personal tone.
The reports I write at work are very similar to the ones we learn in the book such as progress reports, letters of approval, information reports, and a recommendation report. I have delivered business letters/reports in person, by mail, by fax, by email, online.