What is the search form code file for the theme??

Hey there, i have already posted my problem on replacing the default search option for the theme Editorial. I am using a child theme which i create. I want to use google cse in this theme, but do not want to change the search form style. I know there are many plugin, widget or html code to use cse in sidebar. I will serve my purpose partly, because i have to customize the form again and that will not work with the toggle search option available beside the header menu (that is the major problem for me). So i do some research, as i am not so good in web design, i learn that if i could change the “form action” of the default search form, i could use the result only option in cse. But the problem is i could not find any file where that “form action” is available, or i may not understand where it is located. I have checked the “search.php”, “template part/content-search.php” files too, where the form code may exist in normal case. Therefore, i need some help. If anyone know, please help me to find that code file.
Thanks in advance

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