interfacelab

NOTE: This plugin requires PHP 7.1x or higher
The ILAB Docs plugin allows you to integrate help documentation for your WordPress theme or plugin directly 
into the WordPress admin.
Documentation is written in Markdown, with special extensions that make writing documentation in markdown easy. These 
extensions allow linking to other markdown files, linking to admin pages, video embeds, displaying a table of contents 
and other features. ILab Docs also has integrated search functionality for easily searching your documentation.
For examples integrating this documentation plugin with your plugin or theme, check out these examples:
<ul>
<li><a href="https://github.com/Interfacelab/ilab-docs-example-plugin" rel="nofollow ugc">Example plugin with documentation</a></li>
<li><a href="https://github.com/Interfacelab/ilab-docs-example-theme" rel="nofollow ugc">Example theme with documentation</a></li>
</ul>

WP Help Docs

Directly integrate markdown based help documentation for your WordPress theme or plugin into the WordPress admin for your end users and clients.

WordPress.org

Ella

This plugin allows you to create documents with WordPress, and to share them with others so they can also read and edit. Share the unique link to let anyone edit, or restrict access to specific email addresses.
With the Gutenberg plugin, Docs supports real-time collaborative editing — multiple users can edit the same document simultaneously, seeing each other’s cursors and changes live.
<h3>Sharing</h3>
The share panel (in the document sidebar) lets you control access:
<ul>
<li>Anyone with the link — anonymous users get a randomly generated animal name and emoji avatar (e.g. “Anonymous Fox”). They can edit text but cannot upload files.</li>
<li>Specific people — invite collaborators by email. They receive a magic link to access the editor. Email-invited users can upload files.</li>
<li>Existing users — add collaborators from the user autocomplete. They get full editing and upload access.</li>
<li>Restricted — only the document author and invited people can access.</li>
</ul>
<h3>How it works</h3>
Documents live entirely in wp-admin — there’s no public frontend. Each doc gets a unique and secret shareable URL that opens the editor directly.
Anonymous visitors don’t create any database entries. Their identity exists only in a browser cookie and disappears when it expires.
Email-invited people are created as real WordPress users (without a role) so their edits show up in revision history. They log in via magic links sent to their email.

Docs

how it works? 
Can I use it in the classic editor?

how it works

Create and share documents with WordPress!

WP Help Docs vs Docs