What is the difference between using echo and return in PHP when returning a value from a function?

When returning a value from a function in PHP, the main difference between using `echo` and `return` is that `echo` is used to output a value to the screen, while `return` is used to return a value from a function. If you use `echo` to return a value from a function, the value will be displayed on the screen, but it will not be available for further processing in the code. On the other hand, using `return` will actually pass the value back to the calling code, where it can be stored in a variable or used in other operations.

// Example using echo
function getValueWithEcho() {
    echo "Hello World";
}

$value = getValueWithEcho(); // Output: Hello World
echo $value; // Output: (empty)

// Example using return
function getValueWithReturn() {
    return "Hello World";
}

$value = getValueWithReturn();
echo $value; // Output: Hello World