Writers seldom have complete control over length requirements. Journalists usually write within strict word limits set by their editors, business writers routinely aim for conciseness, and most college assignments specify an approximate length.

Your writing situation may also require a certain document design. Specific formats are used in business for letters, memos, and reports. In the academic world, you may need to learn precise disciplinary and genre conventions for lab reports, critiques, research papers, and so on. For most undergraduate essays, a standard format in a particular citation style (MLA, APA, Chicago) is acceptable.

In some writing situations, you will be free to create your own design, complete with headings, displayed lists, and perhaps visuals such as charts and graphs.