Last updated April 10, 2012.
If you read Drupal Community Documentation, you can write it. Everyone with a Drupal.org account can help, not just members of special teams or people who've received permission.
One good way to get started helping with Drupal documentation is to check out the New Contributor Tasks section on Drupal.org. These tasks are described in detail, with links to all the background information you would need, and are designed to take less than an hour each (of course, you can repeat them!).
Or, read on to find some other quick ideas... You will first need to create a Drupal.org account, and then you can:
- Edit pages directly by clicking on the "Edit" tab. Most Community Documentation pages on Drupal.org are open to editing by all Drupal.org users. We do have a few pages that are "locked" for various reasons. Don't worry about mistakes. We keep revisions of all handbook pages so we can always go back to a previous version, or look at what has changed and grab some deleted text, if needed. Be sure to familiarize yourself with the Drupal.org style guide.
- Find a page to edit by visiting the Documentation Management view page (must be logged in). Search for pages with a few comments (you can incorporate them into the page), or pages with status such as "needs copy/style review" or "needs technical review" (edit the page, and change the status to "no known problems" when it's fixed up).
- Add new documentation pages. All Drupal.org users can add new pages to the Community Documentation (click the Add Child Page link at the bottom, to add a page under a particular page in the hierarchy). Be sure to familiarize yourself with the Drupal.org style guide.
- If you know there's an error on a page but are not sure how to fix it, add a comment to the page, and then edit it to change the page status to "needs technical review" or another appropriate status.
- If all else fails, or if a change you'd like to make is fairly major and you're not sure about it, you can submit an issue to the "Documentation" project. See if an issue already exists for your suggestion by searching the issue queue; if so, you should instead add comments to the existing issue. For more details, see Documentation issue reports, or watch this video on how to use the Drupal issue queues to contribute to Drupal.