JSFiddle - React, Tailwind, and code Playground

HTML

<form method="post" name="form_BE_box" action="">
<input type="email" name="mail" placeholder="Votre adresse mail" id="MAIL"/>
<button class="button" type="submit">S'inscrire</button>
<div>
<input type="checkbox" checked="checked" value="Partenaire" name="fou" /> Cochez ici pour s'inscrire aux communications partenaire
</div>
</form>