How to rewrite the url by rewrite rule?

Question

I am having a link something like

www.example.com/index.php?name_slug=xyz

and retrieving data from url by

if (isset($_GET['name_slug'])) {
      
      $slug = $_GET['name_slug'];
       $r=mysqli_query($con,"SELECT * FROM users where name_slug = '$slug' ");
    $m = mysqli_fetch_array($r)

Now i need to rewrite the url as

www.example.com/xyz