<a href="https:&#x2F;&#x2F;letsencrypt.org&#x2F;howitworks&#x2F;technology&#x2F;#domain-validation" rel="nofollow">https:&#x2F;&#x2F;letsencrypt.org&#x2F;howitworks&#x2F;technology&#x2F;#domain-valida...</a><p>There&#x27;s a bit more to it than &quot;allowing subdomain creation&quot;. You will need control over the DNS records, or ability arbitrarily change the page (essentially).