https://ecounion.ru/wp-content/themes/ecounion/assets/js/buttons.js?ver=1.0

1// specifies behaivor for buttons on 
2// index.html, article1-page.html, article2-page.html
3
4let buttonForm = `<!-- Modal form: write letter to EcoUnion -->
5<div id="write-form" class="c_form_modal">
6<form action="post" class="c_form_template">
7    <div class="l_m-auto">
8        <img src="<?php echo get_theme_file_uri( '/assets/img/svg/x-icon_green.svg') ?>" alt="close form" class="c_form_close">
9    </div>
10    <h4 class="l_mt-40 b_eco-d-green">Написать письмо</h4>
11    <input type="text" value="ФИО" class="c_form_input l_mt-40 b_body b_eco-grey">
12    <input type="text" value="Организация" class="c_form_input l_mt-40 b_body b_eco-grey">
13    <input type="text" value="Email" class="c_form_input l_mt-40 b_body b_eco-grey">
14    <input type="text" value="Тема письма" class="c_form_input l_mt-40 b_body b_eco-grey">
15    <textarea name="" id="" cols="30" rows="5" class="c_form_input l_mt-40 b_body b_eco-grey">Текст письма</textarea>
16    <p class="b_footer l_mt-15"><span class="b_eco-green">*</span> Поля обязательные для заполнения</p>
17    <input type="radio" id="policy" class="l_mt-40">
18    <label for="policy" class="b_body">Я даю согласие на обработку персональных данных и подтверждаю, что ознакомился<br>с <a href="#" target="-blank" class="a_link b_eco-green">политикой конфиденциальности</a> Экологического союза </label>
19    <button class="c_btn c_btn_g b_btn b_eco-white l_mt-70 l_m-auto">Отправить</button>
20</form>
21</div>` 
22
23if (document.getElementById('returnForm')) {
24    let returnForm = document.getElementById('returnForm');
25    
26    returnForm.addEventListener('click', function() {
27        returnForm.insertAdjacentHTML('afterend', buttonForm);
28    })
29}