How to create a function Javascript

function functionName() {
  // function body
}

Here's an example of a function that adds two numbers:

function add(a, b) {
    return a + b;
}

let result = add(2, 4); // Calling the function with 2 and 4
console.log(result); // This will print 6

In this example, the add function takes two parameters, a and b, and returns their sum. When calling add(2, 4), it computes 2 + 4, returns 6, and stores the result in the result variable, which is then printed to the console.

In JavaScript, the return statement stops a function's execution and sends a value back to the caller. Once a return is executed, the function exits immediately, and any code after it is not executed.