{% extends 'base.html.twig' %}{% block body %} <h2>Demo merge pdf</h2> {{ form_start(form, {attr: {'target': '_blank'}}) }} {{ form_widget(form) }} <div class="form-group text-right"> <input type="submit" class="btn btn-primary mt-2" value="Merge"> </div> {{ form_end(form) }}{% endblock %}