Example of using PHPWord to convert html to docx. Install PHPWord with Composer.

index.php

<?php
require_once './vendor/autoload.php';

// install phpword with composer:
// composer require phpoffice/phpword

use PhpOffice\PhpWord\Style\Language;
use PhpOffice\PhpWord\PhpWord;
use PhpOffice\PhpWord\Shared\Html;

// New Word Document
$pw = new PhpWord();
$pw->getSettings()->setThemeFontLang(new Language(Language::ES_ES));
// ES_ES -> Español/Spanish
$str = <<<MyHTML
<p style="font-size:30px; text-align:center;" >What is Lorem Ipsum?</p>
<p style="font-size:20px; margin: 20px;" >Lorem Ipsum is simply dummy text
of the printing and typesetting industry. Lorem Ipsum has been the industry's
standard dummy text
ever since the 1500s, when an unknown printer took a galley of type and
scrambled it to make a type specimen book. It has survived not only five
centuries, but also the leap into electronic typesetting, remaining essentially
unchanged. It was popularised in the 1960s with the release of Letraset sheets
containing Lorem Ipsum passages, and more recently with desktop publishing
software like Aldus PageMaker including versions of Lorem Ipsum.</p>
<p  style="font-size:30px; text-align:center;">Why do we use it?</p>
<p style="font-size:20px;" >It is a long established fact that a reader will be
distracted by the readable content of a page when looking at its layout. The
point of using Lorem Ipsum is that it has a more-or-less normal distribution of
letters, as opposed to using 'Content here, content here', making it look like
readable English. Many desktop publishing packages and web page editors now use
Lorem Ipsum as their default model text, and a search for 'lorem ipsum' will
uncover many web sites still in their infancy. Various versions have evolved
over the years, sometimes by accident, sometimes on purpose (injected humour and
 the like). </p>
<p style="font-size:30px; text-align:center;" >Where does it come from?</p>
<p style="font-size:20px" >Contrary to popular belief, Lorem Ipsum is not simply
random text. It has roots in a piece of classical Latin literature from 45 BC,
making it over 2000 years old. Richard McClintock, a Latin professor at
Hampden-Sydney College in Virginia, looked up one of the more obscure Latin
words, consectetur, from a Lorem Ipsum passage, and going through the cites of
the word in classical literature, discovered the undoubtable source. Lorem Ipsum
comes from sections 1.10.32 and 1.10.33 of "de Finibus Bonorum et Malorum" (The
Extremes of Good and Evil) by Cicero, written in 45 BC. This book is a treatise
on the theory of ethics, very popular during the Renaissance. The first line of
Lorem Ipsum</p>
MyHTML;

echo $str;

$properties = $pw->getDocInfo();
$properties->setCreator('Tu nombre');
$properties->setTitle('El titulo del documento');

$properties->setDescription('Una descripción');
$properties->setCategory('Tu categoria');
$properties->setLastModifiedBy('MTu nombre');
$properties->setCreated(mktime(0, 0, 0, 10, 14, 2022));
$properties->setModified(mktime(0, 0, 0, 10, 14, 2022));
$properties->setSubject('Subject');
$properties->setKeywords('my, key, word');


$section = $pw->addSection();

Html::addHtml($section, $str, false, false);
$pw->save("HTML.docx", "Word2007");

HTML.docx