Is it still required for Codecanyon items to have offline documentation? Or is it sufficient to have online documentation and include link in the download package? What is the proper way to include the link to online documentation? And which tool are you using to create your documentation?
I was using documenter for years, but now I found that gitbook is much better tool, but offers only online version on free plan. Also documenter seems to not work anymore.
Thanks 
As far I know at least you have to include a documentation folder and include a html or pdf file (required) where you can include your full documentation or set a link (text/button) of your online documentation there.
I think better is create your own style template for the documentation of your items. So that you can reuse the template for all of your items.
Thanks
You can create an online documentation and create “documentation” folder with the index.html that states " click here for the online documentation" this should be enough.
Thanks for you replies, I made like @ki-themes suggested.