backend/app/views/userCreate.php

<form action="/admin/user/" method="post">
    Логин:<br>
    <label>
        <input type = "text" name = "username" required size="50" autofocus placeholder="Логин">
    </label> <br> <br>

    Пароль:<br>
    <label>
        <input type = "text" name = "password_hash" required size="50" placeholder="Пароль">
    </label> <br> <br>

    Email адрес: <br>
    <label>
        <input type="Email" name="email" required>
    </label> <br><br>

    <input type = "submit" value="Подтвердить">
    <input type="reset">
</form>