How could i make a simple ip display text on my HTML document?

So i have a simple HTML document. Code is:

<!DOCTYPE html>
<center><h1>This sub-domain is owned by</h1></center>
<center><h2>Please go back to</h2><center>
<center><h3>Stop checking out this site</h3><center>

Can somebody modify this HTML document to PHP document so it replaces text IP with user’s ip? I can add javascripts or other files to my website too, if its needed to make this posibble. I just need someone to modify this code so it displays user’s ip instead of text: IP.

<center><p><?= $_SERVER['REMOTE_ADDR'] ?></p></center>