In cooked mode data is preprocessed before being given to a program, while raw mode passes the data as-is to the program without interpreting any of the special characters.
Backspace, delete, and Control-D are typically used to enable line-editing for the input to the running programs, and other control characters such as Control-C and Control-Z are used for job control or associated with other signals.
The precise definition of what constitutes a cooked mode is operating system-specific.
In cooked mode, the terminal line discipline processes the characters "ABC
Technically, the term "cooked mode" should be associated only with streams that have a terminal line discipline, but generally it is applied to any system that does some amount of preprocessing.