Project documentation for each part of the project: technical / user / test documentation

Description:
How should a web application look, work and what does it want to achieve? At the beginning, only the manager has all this in his head, and it is impossible for the project to depend on one person who is the bearer of the idea.
In addition, if the human factor comes into play and the project is long-lasting, we don't have to remember everything. Project documentation should be a part of every project – the description of user stories, the description of the UX design, testing and technical documentation.

Links:
https://www.projectmanager.com/blog/great-project-documentation,
https://www.indeed.com/career-advice/career-development/project-documentation

Keywords:
Project management, documentation, project maintenance, software development, software testing

Motivation:
Software development is a very specific part and there is no doubt about the importance of project documentation – for testers, developers and managers. Keeping and maintaining documentation may seem time-consuming, but as a result, it saves time not only for the manager, but also for the development team.

Requirements/Prerequisities:
Nothing specific, just the ability to write factually and concisely

Level:
generic: high level abstract best practice, metalevel category (e.g. manage architectures)

Application domain:
Medicine/Healthcare, Education (Technology enhanced learning), Data science (analysis & visualisation), Software engineering

Main phase:
Generic: Requirements/Exploration, Generic: Design/Plan, Development: Implementation/Code/Build, Development: Testing

Related literature:

https://www.sciencedirect.com/science/article/pii/S0164121299000941
https://dl.acm.org/doi/abs/10.1145/585058.585065

In which projects do/did you use this practice?
SIMUportfolio