The push-up overlay menu, visible in the upper right corner, uses the popup feature of Elementor builder.
Popups are call-to-action modal windows that popup and overlay the page at a specified moment or under specific triggers and conditions. Popups are designed to focus a user’s attention once they have taken an action.
To begin, navigate to the Toolbar > Edit with Elementor > Overlay Menu
Or go to Templates > Popups. Control the layout, conditions, rules and styles of the popup, and then design the popup content.