bootstrap dropdown select form with option to enter custom value code example

Example: how sat drop down list in bootstrap 4 like a row and column

<div class="form-row">
        <div class="form-group col-2">
        </div>
        <div class="form-group col-5">
        </div>
        <div class="form-group col-5">
        </div>
      </div>

      <div clas="form-row">
        <div class="form-group col-4">
        </div>
        <div class="form-group col-4">
        </div>        
        <div class="form-group col-4">
        </div>        
      </div>