'Dynamic Documents' are projects or papers that are developed using prominent tools such as R-markdown or JuPyTer notebooks (the two most prominent tools).
The salient features and benefits of this approach include:
Integrated data analysis and reporting means the data analysis (as well as math/simulations) is done and reported in the same space that the results and discussion are presented. This is made possible through the concealment of 'code blocks'.
Transparent reporting means you can track exactly what is being reported and how it was constructed:
Making the process a lot less error-prone
Helping readers understand it better (see 'explorable explanations')
Helping replicators and future researchers build on it
Other advantages of these formats (over PDFs for example) include:
Convenient ‘folding blocks’
Margin comments
and links
Integrating interactive tools
Some quick examples from my own work in progress (but other people have done it much better)