There is a EditThisPage link at the bottom of every page. Just click on it to edit the currently shown page.
You'll see a large input box appear with the current content inside. Just make your additions or fix some typing errors and push the [Save] http://reallycheaphealthinsurance.com/get-a-cheap-health-insurance-quote/button.
You do not need to register or something else to use this function!
Now go to the SandBox to play a bit.