Is there diffrence to get MAC address PC and Cellphone?

I would like to get MAC address in Laravel project. my Laravel Framework is 6.18.8

I use below code and I could get MY PC's MAC address sucessfully However When I access this page by my cellphone I can't get MAC address. I looked Mysql database's table, the MAC column was empty. Could someone teach me right code please?

THis is my current code

 function getMAcAddressExec()
    {
            return substr(exec('getmac'), 0, 17); 
    }

via Chebli Mohamed