You are already writing comments for your R code so you may be wondering why you need to document code with a Notebook tool, such as RMarkdown. You can find several RMarkdown examples here. Notebook tools are particularly useful when you share your code and analysis with non-coders or non-R coders. RMarkdown can help you create interactive web document with text, code and results of executing that chunk of code all in one place. Many R users choose to document and share code with RMarkdown, but it can be used to document scripts writing in other programming languages, such as Python and SQL.