iris/_examples/mvc/login/web/views/user/login.html

<form action="/user/login" method="POST">
    <div class="container">
        <label><b>Username</b></label>
        <input type="text" placeholder="Enter Username" name="username" required>

        <label><b>Password</b></label>
        <input type="password" placeholder="Enter Password" name="password" required>

        <button type="submit">Login</button>
    </div>
</form>