To begin, navigate to the Toolbar > Edit with Elementor > Search Popup:
Or go to Templates > Popups > Search Popup > Edit with Elementor. Control the layout, conditions, rules, and styles of the popup.
You can find more information regarding the Search Widget here: https://elementor.com/help/search-widget/
Please check these guides for further information:
Read more about the Elementor Popups
Guide to Vamtam Elementor Builder
How to trigger the popup from the header search icon?
To begin, navigate to the Toolbar > Edit with Elementor > Header - Home Modern:
Click on the "Edit" icon of the button. You can edit or remove the popup connection in the Link field:
Please follow the detailed tutorial for how to "Create a Button to Trigger an Onclick Popup in Elementor" here:
https://www.youtube.com/watch?v=-29XXbJLnQM
https://elementor.com/help/how-to-trigger-a-popup-on-a-link-click/