No PHP · no backend
The old tutorial is a contact.php that calls mail(). GitHub Pages, Hugo, Astro, and Cloudflare Pages cannot run that file. You need a form backend, not a PHP host.
<form action="https://smote.sh/f/FORM_ID" method="POST"> <input name="email" type="email" required> <textarea name="message" required></textarea> <input type="hidden" name="_redirect" value="https://yoursite.com/thanks"> <button>Send</button> </form>
That is the whole server. Field names become inbox columns. Hidden _redirect sends people to your thank-you page.
PHP is a backend. A Cloudflare Worker or Netlify Function that talks to an SMTP API is also a backend. smote is the action URL so you do not keep either. Text fields only — no file uploads.
Get an action URL Static site guide
Also: GitHub Pages · Hugo · Astro · Jekyll · Cloudflare Pages · Any static site