1
You can use the class input-group-addon to do as you wish. 
See the low example:
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet" />
<div class="form-group">
  <div class="input-group">
    <span class="input-group-addon">
      <i class="glyphicon glyphicon-calendar"></i>
      </span>
    <input class="form-control left-border-none" type="text" placeholder="Ida" />
  </div>
</div>
<form class="form-inline">
  <div class="form-group">
    <label class="sr-only" for="exampleInputAmount">Amount (in dollars)</label>
    <div class="input-group">
      <div class="input-group-addon">$</div>
      <input type="text" class="form-control" id="exampleInputAmount" placeholder="Amount">
      <div class="input-group-addon">.00</div>
    </div>
  </div>
</form>
Just remembering that the element
buttonhas, by default,tabindexequal to 0 and enters the navigation list by keyboard. In this case, as it will be merely decorative, it is interesting to definetabindex="-1"so that the focus is passed directly to theinput. Further reading: How and where tabindex works?. Use semanticallyinput-group-addon, as specified in the other answer, makes more sense.– Woss