Custom template for collection form

01-PersonFormType.php

<?php

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilder;

class PersonFormType extends AbstractType
{
    public function buildForm(FormBuilder $builder, array $options)
    {
        $builder
            ->add('name')
            ->add('addresses', 'collection', array(
                'type' => new AddressFormType(),
                'allow_add' => true,
            ));
    }

    public function getName()
    {
        return 'form_person';
    }
}

02-AddressFormType.php

<?php

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilder;

class AddressFormType extends AbstractType
{
    public function buildForm(FormBuilder $builder, array $options)
    {
        $builder
            ->add('city')
            ->add('street');
    }

    public function getName()
    {
        return 'form_address';
    }
}

03-form.html.twig

{% form_theme form _self %}

<form action="{{ app.request.uri }}" method="post">
  {{ form_row(form.name, {'label': 'Name:'}) }}
  <h3>Addresses</h3>
  {{ form_widget(form.addresses) }}
  <input type="submit" />
</form>

{% block form_address_row %}
  {{ form_row(form.city, {'label': 'City:'}) }}
  {{ form_row(form.street, {'label': 'Street:'}) }}
{% endblock %}

04-alt-form.html.twig

{% form_theme form _self %}

<form action="{{ app.request.uri }}" method="post">
  {{ form_row(form.name, {'label': 'Name:'}) }}
  <h3>Addresses</h3>
  <div data-prototype="{{ form_row(form.addresses.get('prototype'))|e }}">
  {% for child in form.addresses %}
    {{ form_row(child) }}
  {% endfor %}
  </div>
  <input type="submit" />
</form>

{% block form_address_row %}
  {{ form_row(form.city, {'label': 'City:'}) }}
  {{ form_row(form.street, {'label': 'Street:'}) }}
{% endblock %}