For the instructions to be understood by the computer it must be written in a special code language. What is this code language called?

Machine language (or machine code) is the native binary language that computers directly execute - it consists of 1s and 0s that the CPU interprets as instructions. All other programming languages must ultimately be translated or compiled into machine language before the computer can understand and execute them. Assembly language uses mnemonics to represent machine instructions, while high-level programming languages are more human-readable but require compilers or interpreters.