Documentation is only available on the web. I consists of the website and blog, Github and SourceForge repositories, User Manual, Wiki, Forum, Zulip chat Forum and IRC #librecad.

The User Manual and this DokuWiki containing tutorials and how-to supercede the old wiki.

The LibreCAD User Manual hosted at Read the Docs contains:

• Installation instructions including building from source and configuration of LibreCAD.
• Reference section describing the commands and their parameters.
• User guides providing steps to perform common tasks.

It is the primary source of documentation.

Other manual:

• http://www.heikell.fi/downloads/LibCAD_220rc1.pdf

Note that these manuals may be for older versions of LibreCAD and may not reflect the command or layout found in the latest release of LibreCAD.

You may find older documentation for version 1.0 and 2.0, and some French and Spanish documents, in the old wiki.