JSFiddle - React, Tailwind, and code Playground

HTML

<label>Escolhe o campo:
    <select>
        <option value=""></option>
        <option value="nome">Nome</option>
        <option value="idade">idade</option>
    </select>
</label>

<label>nome
    <input name="nome" type="text">
</label>
<label>idade
    <input name="idade" type="text">
</label>

JavaScript

var select = document.querySelector('select');
select.addEventListener('change', function() {
    var input = document.querySelector('[name="' + this.value + '"]');
    if (input) input.focus();
});