JSFiddle - React, Tailwind, and code Playground

HTML

<div class="main_menu_item">
    <a href="/billing/">Меню</a>
    <div class="submenu">
        <div><a href="/billing/">Меню 1</a></div>
        <div><a href="/billing/">Меню 2</a></div>
        <div><a href="/billing/">Меню 3</a></div>
    </div>
</div>

CSS

.submenu
{
    display: none;   
    position: absolute;
    text-align: left;
    background-color: white;
    padding: 5px;border: 1px solid #6B93FF;
}

div.main_menu_item:hover div
{
    display: block;
}