How to implement popup from wordpress main menu button?

Question

PHP

Hello.
Interested in an elegant (well, or at least some) possibility of implementing a call to the "contact form 7" plugin form in the pop-up window of the "flaxbox" plugin directly from the main menu item. It works fine only in the body of the post or in the sidebar. I understand that the "flaxbox" plugin included in the template block does not process. This can be done in a human way. I'm trying to understand, because of my little knowledge and skills in PHP I can't understand and write it, or should it not work at all?
The site is here: himki.nixorclinik.ru (as planned, it should pop up by clicking on the "Sign up" menu item)
How it works on the contact page.

Answer 1

This plugin will help you https://wordpress.org/plugins/popups/