JSFiddle - React, Tailwind, and code Playground

HTML

<table>
    <tr>
        <td align="right"> <font face="arial" color="blue" size="-1">Senha do Usuário :</font>

        </td>
        <td>
            <input type="text" data-title="Senha padrão para novos usuários." align="left" name="tx_senh_usua" size="7" value="SEDS">
            <td align="right"> <font face="arial" color="blue" size="-1">Nome :</font>

            </td>
            <td>
                <input type="text" data-title="Nome" align="left" name="tx_nome_usua" size="7" value="">
            </td>
            <td> <span style="color: blue;" class="tooltip">?</span>

            </td>
    </tr>
</table>

CSS

table {
    margin-top: 100px;
    position: relative;
}
.tooltip {
    display: inline;
    position: relative;
}
.tooltip:hover:after {
    padding: 5px 15px;
    width: 220px;
    border-radius: 5px;
    background: #333;
    background: rgba(0, 0, 0, .8);
    content: attr(data-title);
    position: absolute;
    left: 20%;
    bottom: 26px;
    z-index: 98;
    color: #fff;
}
.tooltip:hover:before {
    border: solid;
    border-color: #333 transparent;
    border-width: 6px 6px 0px 6px;
    content:"";
    position: absolute;
    left: 50%;
    bottom: 20px;
    z-index: 99;
}

JavaScript

document.querySelector('.tooltip').onmouseover = function () {
    var texto = document.activeElement.getAttribute("data-title");
    if (texto) this.setAttribute("data-title", document.activeElement.getAttribute("data-title"));
}