Before getting started coding with CodeIgniter we need to understand the folder structure of CodeIgniter. CodeIgniter has its own folder structure. When you have mapped the CodeIgniter folder to "www" folder you will find the below structure. Application folder is the main folder, where you will find the sub-folders in it (refer below screen shot). In the above screen shot you will find the all the folder, here can start coding to build your application. The 'Controller', 'Model', 'View' are the folders where you will add or update and delete files. 'Config' folder is responsible for all configuration like database, routing and etc. 'Libraries' folder is the folder where all the predefined libraries resides in it.