Enfold – Add a custom Font Resizer in the Navigation Menu or in the Header

I would like help on adding a font resize to the header of the Enfold theme I am using at http://neighborsnetworkfl.org

I have seen lots of sites with a very simple one-click button that cycles through different text sizes so users can adjust the text size for their disability. I have found plugins and widgets that let you add this function to the page in the widget or sidebar areas, like I have done on the right footer of this website. But I would much prefer it be a permanent option maybe to the right of the magnifying glass search function on the navigation menu or even on the top bar. Whatever is easiest.

Would someone be able to help me? I even have one of the plugin’s codes that could be used, if needed. I just don’t know where to insert it to implement it properly.

Thank in advance!