How to use $submission->set_response

Hello @diddimy

This feature is not available in our plugin and is also not part of our plugin.
Our plugin is used to display contact form 7 in any part of the webpage through the Elementor widget and Gutenberg block.

A hook is available in contact form 7 to add functionality before sending an email.
You can visit this link: https://contactform7.com/2018/01/31/contact-form-7-50/

Best Regards,
HT Plugins

Thank you for your answer – and sorry, that was the wrong forum.