JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" maxlength="1" class="small" />
<input type="text" maxlength="1" class="small" />
<input type="text" maxlength="1" class="small" />
<input type="text" maxlength="1" class="small" />

CSS

.small {
    width:140px;
    text-align:center;
}

JavaScript

$(".small").keyup(function () {
    $(this).next().focus();
});