Warning: mysqli_fetch_array() expects parameter 1 to be mysqli_result, string given in C:\xampp\htdocs\test\vendor\search_form.php on line 16

  <form action="search.php" method='GET' class="form_search">
    <div id='search_form'>
      <li><a><input class="search" placeholder="Search" type="search" name="search" id="search"></a></li>
      <li><a><button class="btn_search"><i  class="fas fa-search"></i></button></a></li>
    </div>
    
  </form>

include_once "vendor/search_form.php";

function search_user () {

global $conn;
if(isset($_GET['search'])) {
    $search_query = htmlentities(mysqli_real_escape_string($conn, $_GET['search']));
    $get_user = "SELECT * FROM users WHERE name LIKE '%$search_query%' OR surname LIKE '%$search_query%' ";
} else {
    $get_user = "SELECT * FROM users";
}
$run_user = mysqli_query($conn, $get_user);

while($row_user = mysqli_fetch_array($get_user)) {
    $user_id = $row_user['id'];
    $user_name = $row_user['name'];
    $user_surname = $row_user['surname'];
    $user_country = $row_user['country'];
}    

}