Unfortunately it isn’t that simple. In this case ‘search’ text will appear under the magnifier/search icon. I would like to have visible only icon there. I’ve found something like this:
$items .= '<li id="menu-item-search" class="noMobile menu-item menu-item-search-dropdown"><a href="?s=" rel="nofollow">;</a></li>';

in https://kriesi.at/support/topic/replace-toggle-icon-with-another-entypo-fontello-font-or-use-a-png/

I cant figure out how to get magnifier icon not the character you can see here http://www.fileformat.info/info/unicode/char/e803/index.htm

Regards,
Pawel