bootstrap4 file upload
<div class="input-group">
<div class="input-group-prepend">
<span class="input-group-text" id="inputGroupFileAddon01">Upload</span>
</div>
<div class="custom-file">
<input type="file" class="custom-file-input" id="inputGroupFile01"
aria-describedby="inputGroupFileAddon01">
<label class="custom-file-label" for="inputGroupFile01">Choose file</label>
</div>
</div>