thing

<form action="#" method="post">
  <div class="form-group">
    <label for="username_input"><span class="glyphicon glyphicon-user"></span> Your Username</label>
    <div class="input-group">
      <span class="input-group-addon" id="username_addon">@</span>
      <input type="text" class="form-control" id="username_input" placeholder="username">
    </div>
  </div>
  <div class="form-group">
    <label for="email_input"><span class="glyphicon glyphicon-envelope"></span> Your Email</label>
    <input type="email" class="form-control" id="email_input" placeholder="youremail@place.thing" required>
  </div>
  <div class="form-group">
    <label for="password_input"><span class="glyphicon glyphicon-eye-open"></span> Your Password</label>
    <input type="password" class="form-control" id="password_input" placeholder="secret" required>
  </div>
  <div class="checkbox">
    <label><input type="checkbox" value="" checked>Keep me logged in</label>
  </div>
  <button type="submit" class="btn btn-success">Submit</button>
</form>