WordPress & Elementor.
No plugin, no PHP: WordPress only has to output the form markup. Both routes below work on any hoster, including those that block outgoing mail.
Custom HTML block
Add a “Custom HTML” block in the block editor and paste this. The script tag may sit in the same block.
HTML
Elementor
Drag an “HTML” widget onto the page and paste the same markup. Elementor’s own form widget can also be used: set its action to the submit URL and give the fields the names above.
HTML