<title>Bootstrap 4 Input Group with Dropdowns</title>
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@4.6.0/dist/css/bootstrap.min.css" crossorigin="anonymous">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css">
<script src="https://code.jquery.com/jquery-3.5.1.slim.min.js" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.1/dist/umd/popper.min.js" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/bootstrap@4.6.0/dist/js/bootstrap.min.js" crossorigin="anonymous"></script>
<div class="input-group mb-3">
<div class="input-group-prepend">
<button type="button" class="btn btn-outline-secondary dropdown-toggle" data-toggle="dropdown">
<div class="dropdown-menu">
<a href="#" class="dropdown-item">Link 1</a>
<a href="#" class="dropdown-item">Link 2</a>
<a href="#" class="dropdown-item">Link 3</a>
<input type="text" class="form-control">
<div class="input-group">
<input type="text" class="form-control">
<div class="input-group-append">
<button type="button" class="btn btn-outline-secondary dropdown-toggle" data-toggle="dropdown">
<div class="dropdown-menu">
<a href="#" class="dropdown-item">Link 1</a>
<a href="#" class="dropdown-item">Link 2</a>
<a href="#" class="dropdown-item">Link 3</a>