You can take one of the two following approaches: either create a version log inside the document or use an external versioning tool. Both have their pros and cons, but we recommend going with the latter approach. Just like you use a version control system for your code, you can use it for your documentation. We're not saying you must use a Markdown document stored in a Git repo, but that's a perfectly valid approach as long as you're also generating a business people-readable version of it, be it a web page or a PDF file. Alternatively, you can just use online tools, such as RedmineWikis, or Confluence pages, which allow you to put a meaningful comment describing what's been changed on each edit you publish and to view the differences between versions.
If you decided to take a revision log approach, it's usually a table that includes the following fields:
- Revision: A number identifying which iteration of the...