<link href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/js/bootstrap.min.js"></script>
<script src="//code.jquery.com/jquery-1.11.1.min.js"></script>
<form class="form-horizontal">
<fieldset>
<legend>Cadastro</legend>
<div class="form-group">
<label class="col-md-4 control-label" for="nome">Nome</label>
<div class="col-md-4">
<input id="nome" name="nome" type="text" placeholder="nome" class="form-control input-md" required="">
<span class="help-block">Favor digitar o seu nome completo</span>
</div>
</div>
<div class="form-group">
<label class="col-md-4 control-label" for="telefone">Telefone</label>
<div class="col-md-4">
<input id="telefone" name="telefone" type="text" placeholder="fone" class="form-control input-md" required="">
<span class="help-block">favor digitar o seu telefone</span>
</div>
</div>
<div class="form-group">
<label class="col-md-4 control-label" for="email">e-mail</label>
<div class="col-md-4">
<input id="email" name="email" type="text" placeholder="email" class="form-control input-md" required="">
<span class="help-block">Favor digitar o seu e-mail ex: voce@enviou.com</span>