How to update data from mysql database in PHP

include_once("connection.php");

if(isset($_POST['submit'])){
      $name=$_POST['name'];
      $email=$_POST['email'];
      $password=$_POST['password'];
      $update="UPDATE users SET name='".$name."',email='".$email."',password='".$password."' WHERE       user_id='".$_GET['user_id']."'";
      //PHP 5.X
      $result=mysql_query($insert);
      //PHP 7.X
      $result=mysqli_query($conn,$insert);
      if($result>0){
           echo "Data updated successfully";
      } else {
           echo "Data not saved";
      }
}