title: How can I get a unique Id of each visitor? php
body: <p>In php</p>
  
  <p>I've created for each user a unique URL that if someone opens that URL points to be added to account user.</p>
  
  <p>My problem here is that anyone can do it only once.</p>
  
  <p>How can I get a unique Id of each visitor that does not duplicate?</p>
  
  <p>How can I get information hardware PC or Mobile visitor?</p>