I think it would be great if there were a Notes field for each Macro, where we could enter some useful information. The notes would only be visible while editing, and ideally should be able to be hidden/unhidden. A simple Note icon could could be added to the macro to indicate that there are notes there.
Taking this a bit more, notes for each part/section of a macro would be useful too, especially when first learning Keyboard Maestro,
Yes, currently we only have comment action.
The function "add note" is already available at 
Mark the corresponding action in color and add a note.
If you should work with different colored markings, then do it as @OscarGong already mentioned with the "Comment Action".
Thank @appleianer.
That's not exactly what I was hoping for in a Notes field, but I guess that's all there is.
How did you make that animated GIF?
That could come in handy, without doing a full blown video screencast
I guess @appleianer uses ScreenFlow 
@OscarGong has noticed it correctly 
I am currently working with the current version of Screenflow
Since my English is not very good and written explanations, especially for KM beginners, are not always comprehensible, I prefer to make short gifs.
Pictures often say more than words
The good thing about Keyboard Maestro is that you can automate almost anything
Here is an example of how you @cappy2112 & @OscarGong can quickly create a note and then simply display it:
If I want to create a detailed note with links, various media (YouTube tutorial) etc. for a macro, then I use a bear://x-callback-url/... from the Bear App
Whenever I start the macro, I get the note - the macro pauses until I press "Escape" and then the macro is executed.
The advantage for me is that I can extend the note to iOS or macOS at any time, independent of KM, and I don't have to call KM every time and have to deal with the small input window
I, too, wish that the notes that we add to actions were displayed with the action within the editor. This would be particularly helpful with macros that contain several (or many) actions, some of which have default names that can be ambiguous.
For example, I'm currently porting macros over to KM from QK, and each macro contains a number of clicks. In KM, these actions have names like "Move and Click at (35,110) from the Top Left Corner of the Front Window," Each macro contains several of these click actions, each of which has a title like that.
Ultimately, I'll need to make 12 variations of this macro. So, when editing each, it would be helpful to see—at a glance—all of the the notes I've entered for all actions in the macro, without having to summon each note individually from the menu.
I'm aware we can rename actions, but it's also helpful to be able to see the info contained within the default name.
As such, it would be helpful if we had the option for KM to the display all notes for a given macro. Ideally, if this setting were saved on a per-macro basis, we could ask KM to display only the note (or notes) that we need to see, while others could remain hidden. 
That would be fine as long as there is an easy way to hide a Note, or all Notes in a Macro. Otherwise, they would greatly add to the clutter, making it hard to follow the logic of the actual Actions.
I have found using the following to provide a very acceptable means of documenting a Macro and its Actions:
Rename Actions that combine the built-in name with my specific use of it.
Put blocks of Actions that are closely related into a Group Action, and rename the Group to describe the purpose.
Use Comment Actions when I need more complex or lengthly descriptions of one or more Actions.
HTH.
That's why I put the word option in bold. 