can’t insert data into the database [closed]

I made a form with the code below. As you can see at the bottom of the picture. When I tried submit the data into my database, the data wasn’t inserted.

HERE IS MY db_connection.php 

<?php

 $dbhost = "localhost";
 $dbuser = "root";
 $dbpass = "";
 $db = "test";
 
 $conn = new mysqli_connect($dbhost, $dbuser, $dbpass, $db);

?>

Here is my signup.php

<?
include_once 'db_connection.php';
if(isset($_POST['submit'])){
        if(!empty($_POST['name']) && empty($_POST['owner']) && empty($_POST['location']) && empty($_POST['region']) && empty($_POST['district']) && empty($_POST['street']) && empty($_POST['mobile']) && empty($_POST['address']) && empty($_POST['email'])){
                $name = $_POST['name'];
                $owner = $_POST['owner'];
                $location = $_POST['location'];
                $region = $_POST['region'];
                $district = $_POST['district'];
                $street = $_POST['street'];
                $mobile = $_POST['mobile'];
                $address = $_POST['address'];
                $email = $_POST['email'];

                $sql = "INSERT INTO agency_details ('name', 'owner', 'location', 'region', 'district', 'street', 'mobile', 'address', 'email') VALUES ('$name', '$owner', '$location', '$region', '$district', '$street', '$mobile', '$address', '$email');";
                $RUN = mysqli_query($conn, $sql);

                 header("Location:./index.php?signup=success");
        }
}
?>