search form display no result

Try below code in your footer.php :

<div id="cd-search" class="cd-search">
    <form role="search" method="get" id="searchform" class="searchform" action="<?php echo esc_url( home_url( "https://wordpress.stackexchange.com/" ) ); ?>">
        <input type="search" value="<?php echo get_search_query(); ?>" placeholder="Search..." name="s" id="s" >
        <input type="submit" value="query">
    </form>
</div>

You are missing name="s" id="s" which is needed to add in terms of getting search term.

After search you will see that name in your URL parameter something like : yoursite.com/?s=searched