app/templates/register.html

{% extends "base.html" %}

{% block content %}
<div class="container mt-5">
    <div class="row justify-content-center">
        <div class="col-md-6">
            <div class="card">
                <div class="card-header">Register</div>
                <div class="card-body">
                    <form method="POST">
                        {{ form.hidden_tag() }}
                        <div class="form-group">
                            {{ form.email.label }} {{ form.email(class="form-control") }}
                        </div>
                        <div class="form-group">
                            {{ form.password.label }} {{ form.password(class="form-control") }}
                        </div>
                        <div class="form-group">
                            {{ form.password2.label }} {{ form.password2(class="form-control") }}
                        </div>
                        <button type="submit" class="btn btn-primary">Register</button>
                    </form>
                    <div class="mt-3">
                        <a href="{{ url_for('auth.login') }}">Already have an account? Login</a>
                    </div>
                </div>
            </div>
        </div>
    </div>
</div>
{% endblock %}