How can a global function be defined in PHP to be available everywhere without needing to include it?

To make a global function available everywhere in PHP without needing to include it in every file, you can define the function in a separate file and then include that file in your main PHP script. This way, the function will be accessible in all the files that include the main script.

// global_function.php
function globalFunction() {
    // Function logic here
}

// main_script.php
include 'global_function.php';

// Now you can call globalFunction() anywhere in your main script or its included files
globalFunction();