The simplest way to collect the Client/Visitor IP address using PHP is the REMOTE_ADDR.
Pass the 'REMOTE_ADDR' in PHP $_SERVER variable. It will return the IP address of the visitor who is currently viewing the webpage.

Get the IP address of the website
<?php
echo 'User IP Address : '. $_SERVER['REMOTE_ADDR'];
?>
  
/*
I Hope it will help you.
Namaste
Stay Home Stay Safe
*/

$ip = $_SERVER['REMOTE_ADDR'];

function getIp() {
    $ip = $_SERVER['REMOTE_ADDR'];
 
    if (!empty($_SERVER['HTTP_CLIENT_IP'])) {
        $ip = $_SERVER['HTTP_CLIENT_IP'];
    } elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
        $ip = $_SERVER['HTTP_X_FORWARDED_FOR'];
    }
 
    return $ip;
}

$clientIPAddress=$_SERVER['REMOTE_ADDR']; 

$_SERVER['REMOTE_ADDR']

#to best handle proxies use this:
if (!empty($_SERVER['HTTP_CLIENT_IP'])) {
    $ip = $_SERVER['HTTP_CLIENT_IP'];
} elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
    $ip = $_SERVER['HTTP_X_FORWARDED_FOR'];
} else {
    $ip = $_SERVER['REMOTE_ADDR'];
}