Send Checkbox data by PHPMAILER

I have a form, and I had to include a field in checkbox , how do I send this information via email?

HTML

<form class="form" method="post">       
<div class="visitenosCheckboxItem">
    <input class="css-checkbox" id="checkboxInstitucional" name="checkboxForm[]" type="checkbox">
    <label class="css-label" for="checkboxInstitucional">Institucional</label>
</div>
<div class="visitenosCheckboxItem">
    <input class="css-checkbox" id="checkboxModeloGestao" name="checkboxForm[]" type="checkbox">
    <label class="css-label" for="checkboxModeloGestao">Modelo de Gestão</label>
</div>
<div class="visitenosCheckboxItem">
    <input class="css-checkbox" id="checkboxPlanejamentoEstrategico" name="checkboxForm[]" type="checkbox">
    <label class="css-label" for="checkboxPlanejamentoEstrategico">Planejamento Estratégico</label>
</div>
<input type="submit" class="btn-enviar" name="enviar" value="Enviar">

The HTML that I'm sending goes inside:

$mail->Body = '';