bootstrap seleccionar entrada
<div class="form-group">
<label for="exampleFormControlSelect1">Example select</label>
<select class="form-control" id="exampleFormControlSelect1">
<option>1</option>
<option>2</option>
<option>3</option>
<option>4</option>
<option>5</option>
</select>
</div>
<div class="form-group">
<label for="exampleFormControlSelect2">Example multiple select</label>
<select multiple class="form-control" id="exampleFormControlSelect2">
<option>1</option>
<option>2</option>
<option>3</option>
<option>4</option>
<option>5</option>
</select>
</div>
casilla de verificación bootstrap
<div>
<div class="row">
<div class="form-check form-check-inline">
<input id="checkbox2" type="checkbox">
<label for="checkbox2">Checkbox not checked</label>
</div>
<div class="form-check form-check-inline">
<input id="checkbox3" type="checkbox" checked="checked">
<label for="checkbox3">Checkbox checked</label>
</div>
</div>
</div>
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>
selección de bootstrap
<select class="custom-select">
<option selected>Open this select menu</option>
<option value="1">One</option>
<option value="2">Two</option>
<option value="3">Three</option>
</select>
seleccionar opción usando bootstrap
<div class="form-group">
<label for="expertise" class="col-sm-2 control-label">Expertise:</label>
<div class="col-sm-3">
<select class="form-control inputstl" id="expertise" multiple>
<option>PHP</option>
<option>Java</option>
<option>HTML</option>
<option>CSS</option>
<option>Bootstrap</option>
<option>SQL</option>
</select>
</div>
formularios desplegables en 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>