All projects require some level of documentation. Large projects need a lot of documents because of their complexity and to serve the needs of a big team. Tiny projects may need very little, perhaps only some handwritten lists of things to do and to verify. At a minimum, every project must at least meet the documentation standards mandated by the organization, and may also need documents required by regulatory requirements, industry standards, and methodology needs. (Problem 6 explores some considerations related to standards and methodologies.)
Determining exactly what is useful to include beyond the minimum required for your organization is up to your judgment, but what follows includes some typical project-specific and general documentation.