Input group in bootstrap are put out from controls. By using an input group, we can easily add prepended and appended text or button to the text-based inputs.
We can prepend and append elements to a .form-control by taking all the elements in a <div> under a class .input-group. After that, place your extra content inside a <span> in same <div> by using class .input-group-addon after this you can place the <span> element either before or after the input element.