This code will use ACF's relationship field to display a WP Forms. Place this code snippet in your single template file located in your child theme directory.

single-template_name.php

<?php 
$posts = get_field('wp_forms');
    if( $posts ):
        foreach( $posts as $post):
            $form_id = get_the_ID();
            echo do_shortcode('[wpforms id="' . $form_id . '"]');
            endforeach;
        wp_reset_postdata();
    endif; 
?>