bootstrap 4 form input group

<div class="input-group mb-3">
  <div class="input-group-prepend">
    <span class="input-group-text" id="basic-addon1">@</span>
  </div>
  <input type="text" class="form-control" placeholder="Username" aria-label="Username" aria-describedby="basic-addon1">
</div>

<div class="input-group mb-3">
  <input type="text" class="form-control" placeholder="Recipient's username" aria-label="Recipient's username" aria-describedby="basic-addon2">
  <div class="input-group-append">
    <span class="input-group-text" id="basic-addon2">@example.com</span>
  </div>
</div>

<label for="basic-url">Your vanity URL</label>
<div class="input-group mb-3">
  <div class="input-group-prepend">
    <span class="input-group-text" id="basic-addon3">https://example.com/users/</span>
  </div>
  <input type="text" class="form-control" id="basic-url" aria-describedby="basic-addon3">
</div>

<div class="input-group mb-3">
  <div class="input-group-prepend">
    <span class="input-group-text">$</span>
  </div>
  <input type="text" class="form-control" aria-label="Amount (to the nearest dollar)">
  <div class="input-group-append">
    <span class="input-group-text">.00</span>
  </div>
</div>

<div class="input-group">
  <div class="input-group-prepend">
    <span class="input-group-text">With textarea</span>
  </div>
  <textarea class="form-control" aria-label="With textarea"></textarea>
</div>