Function Declaration

Function is the block of code that performs a specific task. It is a reusable code that can be called multiple times. In PHP, a function is declared using the function keyword followed by the function name and parentheses. The function name should be unique and descriptive. The parentheses may contain parameters that are passed to the function. The function body is enclosed within curly braces {}.

function greeting($name) {
    echo "Hello, " . $name;
}

In this case, 'greeting' is the function name, '$name' is the parameter, and 'echo "Hello, " . $name;' is the operation.