Show a text in menu

You are making mistake in your code. Use this instead:

add_filter( 'wp_nav_menu_items', 'add_search', 10, 2 );

function add_search( $items, $args ) {
    if ( $args->theme_location == 'primary' ) {
        $items .= '<li>Custom HTML</li>';
    }
    return $items;
}

You are welcome ??

Thanks @mqasimkh . But I can’t see Custom HTML in Menu. My menu is like below. May be I am doing mistake here .

$args->theme_location == 'primary'

Look at your theme’s call to wp_nav_menu() and see what args it actually passes. Even if the end result is to display the primary menu, it may not be a passed arg. The default value for theme_location is just ''. Your theme could be passing a “menu” arg instead of “theme_location”.

Thanks @bcworkz. How to know which wp_nav_menu() is working ? I found lots of wp_nav_menu() in my current theme.

What should I pass here $args->theme_location == 'primary' ?

Thanks.

It’s the wp_nav_menu() call on the template that’s responsible for outputting the menu you’re trying to target. If it’s the main menu that’s within the header part of a page, it’s often the call from header.php template (or a referenced template part) if you use a classic theme.

Since you’ve not indicated which theme, I cannot even hazard a wild guess. And unless it’s a free and open source theme, I couldn’t say even if I knew your theme. I can say however, that if “theme_location” isn’t working, your theme is most likely passing a “menu” parameter in order to get the right menu. Either way, the solution is to determine how your theme is managing this.

I can confirm that Muhammad’s suggested code does work on a Twenty Twenty-one theme, so the only reason for failure is a conditional inappropriate for your theme.

But wait! One other possible reason: caching. The code could be working but you’re seeing stale, cached content. Always try clearing any caches, both client and server side before deciding certain code does not work.