bootstrap checkbox styles css code example
Example 1: bootstrap file upload
<form>
<div class="form-group">
<label for="exampleFormControlFile1">Example file input</label>
<input type="file" class="form-control-file" id="exampleFormControlFile1">
</div>
</form>
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>