<?php
include_once 'dbh.inc.php';

$first = $_POST['first'];
$last = $_POST['last'];
$email = $_POST['email'];
$uid = $_POST['uid'];
$pwd = $_POST['pwd'];


$sql = "INSERT INTO users (user_first, user_last, user_email, user_uid, user_pwd)
       VALUES ('$first', '$last', '$email', '$uid', '$pwd');";
       mysqli_query($conn, $sql);

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

<?php
$dbServername = "localhost";
$dbUsername = "root";
$dbPassword = "";
$dbName = "loginsystem";

$conn = mysqli_connect ($dbServername, $dbUsername, $dbPassword, $dbName);

<form action "db/signup.inc.php" method="POST">
                    <input type="text" name="first" placeholder="Firstname">
                    <br>
                    <input type="text" name="last" placeholder="Lastname">
                    <br>
                    <input type="text" name="email" placeholder="E-mail">
                    <br>
                    <input type="text" name="uid" placeholder="Username">
                    <br>
                    <input type="password" name="pwd" placeholder="Password">
                    <br>
                    <button type="submit" name="submit" > Registar</button>


                    </form>