Once granted edit permission, contributors could edit any page on Gitbook and then save and merge the changes by themselves. This is one example commit on Github repo to reflect the updates coming from Git book: Adding Update Document Page Commit.
Usually we grant edit permission to committers and active contributors.
Please contact admin(Email to [email protected] with the content you wanna add) to ask for edit permission for Pinot Gitbook.
Once granted the permission, you can directly working on Pinot Gitbook UI to modify the documentation, and merge changes.