how to get users IP address in php

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
*/

<?php

// Most effective way to get users IP
function get_ip_address(){
    foreach (array('HTTP_CLIENT_IP', 'HTTP_X_FORWARDED_FOR', 'HTTP_X_FORWARDED', 'HTTP_X_CLUSTER_CLIENT_IP', 'HTTP_FORWARDED_FOR', 'HTTP_FORWARDED', 'REMOTE_ADDR') as $key){
        if (array_key_exists($key, $_SERVER) === true){
            foreach (explode(',', $_SERVER[$key]) as $ip){
                $ip = trim($ip); // just to be safe

                if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE) !== false){
                    return $ip;
                }
            }
        }
    }
}

?>