selected bootstrap 4 code example
Example 1: bootstrap select
<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>
Example 2: checkbox html bootstrap 4
<div class="form-check form-check-inline">
<input id="checkbox3" type="checkbox" checked="checked">
<label for="checkbox3">Checkbox checked</label>
</div>