I don't know the meaning of for="inputEmail3", seems its same as id, what is it for? Can I just remove for="inputEmail3" ?
<form>
  <div class="form-group row">
    <label for="inputEmail3" class="col-sm-2 form-control-label">Email</label>
    <div class="col-sm-10">
      <input type="email" class="form-control" id="inputEmail3" placeholder="Email">
    </div>
  </div>