Transfer variables via PHP

Question

How would I get variables for example, our PHP file, data.php, and index.php

If I were to hand over the username to data.php and then that can transfer to other files, how can I get them from other files, not just one? Like, do I use $_SESSION[“Username”]? So I can be like <?php $_SESSION[“Username”]?> or how?

Answer 1

Yes i think that's the most common one to use session_start() on every page.