insert values to data base using php

Allow me to re write your full code for you using the recommended industry standards. First of all you should never ever use the get method $_GET when sending a form data to a database more especially when it contains passwords.

mysql_* api that you are using has been depreciated since I was doing my second year at college, I have graduated and with 3 years working experience, since it was depreciated ;) and was completely remove on php 7.. therefore you should be using mysqli_* or PDO as of v5.5.0 see : Why shouldn't I use mysql_* functions in PHP?

then another issue with your code is at risk of sql inections as @Jay Blanchard have stated above, you can follow his block here to learn more about what he' saying : http://jayblanchard.net/demystifying_php_pdo.html

so to solve what Jay have highlighted above we use something called prepared statements : which prevents against SQL injections.

Then we also in the modern days do not store passwords in plain texts or md5 these days we use password_hash() and password_verify() to store password hash in the database and check the stored password against the user entered password:

in my code you will see : (userNameColumnName,passwordColumnName) userNameColumnName is the column in your table where you will store username and passwordColumnName is teh column in your table where you will store password and make sure the char length is at least 60 chars or better 255.

You can't insert values like this "INSERT INTOadminVALUES ('$name','$password') unless you have exactly two fields in your tabl e as I guess you don't you should atleast have 3. connect.php

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 

then the other page

<?php include("connect.php");

    $errors=false;

if(isset($_POST['submit'])){

    $fields = array("username","password");
    foreach($fields as $fieldname){
        if(!isset($_POST[$fieldname]) && empty($_POST[$fieldname])){

            echo "enter username and password";
            $errors = true;
        }
    }

    if(!$errors){

        $username = $_POST['username'];
        $password = $_POST['password'];

        $hash = password_hash($password);

        $sql = "INSERT INTO admin (userNameColumnName,passwordColumnName) VALUES(?,?)";

        $stmt = $conn->prepare($sql);
        $stmt->bind_param("ss",$username,$hash);
        if($stmt->execute()){

            echo "user added";
        }else{

            echo "error adding user";
            error_log("error".$conn->error); // go and check your error log what was the error
        }
    }

}

?>
<div class="col-md-12">
    <!-- Add admin -->
    <div class="box box-info">
        <div class="box-header with-border">
            <h3 class="box-title">Add admin</h3>
        </div>
        <!-- /.box-header -->
        <!-- form start -->
        <form id="adminForm" class="form-horizontal" action="" method = "POST">
            <div class="box-body">
                <div class="form-group">
                    <label for="inputName" class="col-sm-2 control-label">User 
                    name</label>
                    <div class="col-sm-10">
                        <input type="text" class="form-control" id="inputName" 
                            placeholder="user name" name="username" required >
                    </div>
                </div>
                <div class="form-group">
                    <label for="inputPassword3" class="col-sm-2 control-
                        label">Password</label>
                    <div class="col-sm-10">
                        <input type="password" class="form-control" id="inputPassword3" 
                            placeholder="Password" name="password" required>
                    </div>
                </div>
            </div>
            <!-- /.box-body -->
            <div class="box-footer">
                <input  type = "submit" class="btn btn-info pull-right save" name = "submit" value = "save">
            </div>
            <!-- /.box-footer -->
        </form>
    </div>
    <!-- /.box -->
</div>