How do you define function in php?

A function is defined in php by placing the keyWord function before the chosen function name.

The function name must not match a pre-defined function and has certain limitation as to the characters that can be part of it. Notably, the function name must not contain any spaces. Following the function name are a parenthesis-enclosed, comma-separated list of variables, these variables are called calling parameters and are helpful if the function must process some values or follows diferent branches depending on external variables. Finally the function body is enclosed in curly brackets { }.