How to add text on input border?

Question

Do you know how how to create this additional "*Email" text on my input border?

It should look like this!

Answer 1

.form-group{
  border:1px solid #999;
  margin:10px;
  border-radius: 5px;
}
.form-group>label{
  position:absolute;
  top:-1px;
  left:25px;
  background-color:white;
  color:#666;
  padding:0 5px;
}
.form-group .required{
  color:red;
  padding:0 5px;
}
.form-group>input{
  border:none;
  border:0;
  line-height;100%;
}

<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet"/>
    <div class="form-group">
         <label><span class="required">*</span>Email</label>
         <input type="text" class="form-control input-lg" />
    </div>