How Do Websites Update Their Content?

Well ladies and gents it might be supper obvious and just staring at me but

How do website admins update their content im not talking about a forum like website cus... its quite obvious and im not talking about those prehistoric websites that actualy show a directory when you type admin.php afeter the main link but im talking about those medium-high quality websites that post new documents for their users new notifications which clearly have many admins since one person can not possibly manage all that but do not have a login entry for normal users

So please answer me what is the name of the service they use to update their content .