How to create a modal window by executing an action on approval

Hello everyone, I have little experience with the generation of modal and I want to learn in the best way, in fact, I generated a modal window with the ready and cancel button but I cannot perform the action on my controller. It is possible that by pressing the ready button I can upload my file to my controller. I will add my code.

@if (Auth::user()->hasPermissions(['full-edit'], false))
			    <tr>
				<th>Aprobación documento</th>
				<td><form class="form-inline" enctype="multipart/form-data"  role="form" method="POST" action="{{url('contratos/contrato')}}/{{$entidad->id}}">
  <input type="hidden" name="_token" value="{{ csrf_token() }}" />
  <input type="hidden" name="model" value="bpt:hilti" />
  <label class="btn btn-default" for="file">
    <input id="file" name="file" type="file" style="display:none;" onchange="$('#upload-file-info').html($(this).val());">
      Seleccionar archivo ...
  </label>
  <span class='label label-info' id="upload-file-info"></span>
  <button type="submit" class="btn btn-success">Aprobación de acuerdo {{$entidad->nombre}}</button>
</form></td>
				    </tr>
				   @endif

This functionality is to load the file selected by the user to the controller that is in the path {{url ('contracts / contract'}} / {{$ entity-> id}} I need the modal window to be able to warn the user if is that you want to load the selected file to the controller