Contribute to system extensions¶
The documentation for system extensions is maintained inside the TYPO3 source code, so the contribution workflow is a little different.
For more information about the various contribution workflows, see Documentation contribution matrix.
When it comes to documentation that is contained within the core (like system extension documentation and changelog), you would use Forge to report issues, using the category "Documentation": https://forge.typo3.org/projects/typo3cms-core/issues
The TYPO3 Contribution Guide - Core Development explains the contribution workflow for the core. For making a change to the documentation in the core, you would use the workflow explained in that guide (using Git and pushing to Gerrit).
You can also test the change by rendering locally as in any documentation patch, because all documentation uses a common format and file structure and can be rendered with the same Docker container.
Tip
There is an easy shortcut for minor changes: You can use the Edit on GitHub method for minor changes to system extensions documentation and the changelog. Under the hood, a patch will get created and pushed to Gerrit and you will find a comment in your pull request with information about where to find your patch on Gerrit.

See System Extensions for a list of system extension documentation.
Use the sample extension manual if you want to start new system extension documentation from scratch.