A server-wide admin panel comes at an extra cost. Ask your hoster if you don't have such "useful" things as Plesk or cPanel.
Application-wise, if it's not readily available, odds are that it doesn't exist. So, you either have to pay for it or write it on your own.
The most website has and control panel installed into it making all admins able to edit the website without editing the RAW html files.
Example's of this is EpiServer, Joomla etc..
I wonder how do i get this onto the website? ^^