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. However When I use my cellphone I can't get nothing. I chcked Database MAC column but it's empty.

Could someone teach me right please?

THis is my current code

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

via Chebli Mohamed