We create website so that other people can see and access it.
But sometimes, we want some sub-folder to be hidden from everyone else, including The Master Google for some reason.
We can hide and protect them from public accessed easily. The steps are :

1. For example you want to protect folder secret-folder and all the files, sub-folders in it.
    Create file named .htaccess (with dot, remember) in folder/sub-folder that wa want to protect.
    Example : /var/www/html/secret-folder/.htaccess

2. Edit File .htaccess and write down like this :
    
     AuthUserFile “/var/www/html/secret-folder/.htpasswd”
     AuthType Basic
     AuthName “Please enter your user”
     require valid-user

3. Then, we create File /var/www/html/secret-folder/.htpasswd
     
      htpasswd -bcm .htpasswd username password [Enter]
        username : the username that we want (example : ali)
        password : the password that we want (example : jeRuk$)

    The consist of file .htpasswd will be like this :
    ali:$1$00383777$FDGfdgjdDDGDsirkvflFkYEg.

4. Now, we go to URL http://yourwebsite.net/secret-folder/ on your browser
    We will get Window PopUp ask for user and password.
    If we enter the wrong, or hit the [ESC] button, we will get the page written Authorization Required.
    Now hit the [F5] button to refresh the browser, then enter the right user and password.

Voila! You're great! You can now protect the folder thaht you want :D