dropdown with input field bootstrap code example

Example 1: bootstrap form input select

<div class="col-lg-6 col-md-6 col-12">
  <div class="input-group mb-3">
    <div class="input-group-prepend">
      <select class="form-control select2bs4" name="country_code" id="country_code" style="width: 100%">
        <option value="+91">+91</option>
        <option value="+351">+351</option>
        <option value="+1">+1</option>
      </select>
    </div>
    	<input type="text" name="user" class="form-control" placeholder="Email Or Mobile Number">
    </div>
</div>

Example 2: dropdown forms in bootstrap

<li class="dropdown">
         <a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown            

         <b class="caret"></b></a>
         <ul class="dropdown-menu">
           <li><a href="#"><form role="form">
<div class="form-group">
  <label for="sel1">Select list (select one):</label>
  <select class="form-control" id="sel1">
    <option>1</option>
    <option>2</option>
    <option>3</option>
    <option>4</option>
  </select>
  <br>
  <label for="sel2">Mutiple select list (hold shift to select more than one):</label>
  <select multiple class="form-control" id="sel2">
    <option>1</option>
    <option>2</option>
    <option>3</option>
    <option>4</option>
    <option>5</option>
  </select>
</div>